USSBS Report 78, The Offensive Mine Laying Campaign Against Japan

8/3/2019 USSBS Report 78, The Offensive Mine Laying Campaign Against Japan

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o l /).s .

rCONFIDENTIAL

THE UNITED STATESSTRATEGIC BOMBING SURVEY

. . THE OFFENSIVE MINE LAYING ., CAMPAIGNAGAINST JAPAN

,

.Naval Analysis Division

. 1 November 1.946 .CONFIDENTIAL


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CONFIDENTIAL

THE UNITED STATESSTRATEGIC BOMBING SURVEY

THE OFFENSIVE MINE 'LAYINGCAMPAIGN

AGAINST JAPAN

I Naval Analysis Division

Date of Publica rioa .1 November 1946

~. . . . -

CONFIDENTIAL


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FOREWORD

. This r~pol"t was Ini ttom pdmnrjJy fot the use oj the Uni ted Stctes SI iJ. 'u ,.te . ...c Bo mb ln g un 'e y jJ the nr . ti ff1 " " ' . . - . I re preparnnon 0 tll,ther 11(1)01"tsof II more cornpre-rensrve uuture, .A.lly conclusions or opinions expressed 1',1 tlll 'o ro t Iconsid . d as Iirni .'. , .. - - ~ '~pOl' mus. )6. t ' ~. _ U S ~mlted t~ the specilie l D : L O O 1 1 a i 001'er6(1 and as subje{lt to fUl'tberJJ1 e l p,eb


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TABLE OF CONTENTS

ACKNOWLEDGEMENT

Part I.Introductlon - _- - - - -- - - - - - - -- - -- __- - - -:- - - - - --- - - -- - - _- -- - - -- - - --- - - - -- - - -- -.- --- ---Part II. General Summ",y and .Accompli,hm.uta __ - _- -__ -_ -- - --- - - - -- -- - - -- - - - - -- - - --Part Ill. RistoriCl&l SUlXlm.ary--- - - - -- - -_ - __ --- -- - -- - -- - --- -- - -._- - ---- ------P".t IV. War Les sons and Comments -- - _- -- - _

I. Planning - -- - - -- - - -- - - - - - - - - -- - - - - - - --- - ---- - --- - _- -- - -- - - -- --Need for Adequate Prepnrattou. .Importance of Intell igence.N eed o f Ea rly Decis io n on Mln fng P rogr am.Est imat es of Mines Requi red.II. Operatlor .. -- - - - - - - --- - - - --- - - - - - -- - __-- - ---- - - - _General; . _Almast Too Lit&l e--' j' oo Lat e.Ail" Supedoti ty a nd Ae ria l Min e L ay in g.Tactical Aspeeta, _Tactical Mining,JWl "ti ve Advan ta ge s-Type ", o f Min e LRY" "' .Types of Aircraf t Employed.Mining Tacti cs Employed by Aircraf t.Effectiveness o r Submarine Mining.Employment of Mines and Design of Mine Fields _M ..xtm for Mine Warfare .Persistent "'lin. Lay in g ove r Wid espr ead Area .Inland Waterway&--Their Impor ta nc e a s Min in g T arge ts ,Steril ize. rs and Flooders.Delayed Arming and Ship Counters.~fu.d and Tailored Mines.Secu rity 0r Aeria l Mine Meehan i sms.Fictitious Ml.~e Fields.Aer ia l La id Dummy Mlne.'Teehnical Aspects ~ . . _Technioal Direction.Technical Facilities.Premature E.,>loo iOD!! 0 r Mlnes.Underwater Explosives,Need for Simplification of Preparation.Coordinntion and Liaison . _Coord inat tou wit b. O ther Types of Att .ack .Coc rd tn utd on w if h Majo r S tr at eg y o f Wnr.Off engl v" Min in g, I ts R ela tio n to Subma rin e At ;t ac k, Di re ct A Ir A tt a.k a nd S tr nt eg ic Bomb ing.Impor ta nc e o f Centr al iz ed Coordin at io n by CNO .Army-Navy Cooperat ion.Promulgat ion of Mine Fie ld Informati on ,III. Results of Mill" Att"ck _Eva lu at io n o f Shi ps Sunk . a nd Damaged by Mill,,!;.Eva luat ion of Ship Damage.Added Ef fect of Mining-For cing Enemy to Expand Men and Mater ial to EstablJIlb and MaiutainCountcnn.easures.E loemy Coun tCl'DlClISlIl'CSShipping Delays and Disrupt ion "er~us Shi l>ping Losses,Number o f Min "" P er Shi p C asua .lt y.E ff ec t o f Min in g on Shi p' s Cr ews .IV. Future Poliey -- _Signi llCl&DOOof MiniJlg Campaign to Problem of Countermeasures.Estimated Aeria l Min ing Effor t In Future

Chi r 7e:was p~epared by the Mine Warfare Section of the Officeof theD. ~ .0 ami OperatiollS with the assistance of Military and NavoJ AnoJ .r~'lSloDSof the U. S.Strategic Bombing Survey. YSIS

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IV. IV, ," Lessens and Co"'fIl.onts-Cootlnl looIV. Put"," l'olio}'-Continued

The ~[Inc--,\" Intetnaucnnl Peaco Wenpon.Mine I. .. .IinSand Mine Sweep; ,, !: Coml"'. se l '; Irnc Warfntc.Troining-Offio ers,Trnining-EnLi. ted Personnel.~ V. Couclu>iousand R""""'1!n"ndntioll~ " _, _'_' ,_"" .. .. , __ " _-. , __ , __ _, _. 1 1 . . SUmm".,. of 1nl'o.IIII:",,"" , -' " _

I . Ship cas"oJ! . .. Su. nmary "nd det "i I~d I"t ofS l ,i ps '1, ,, 10 , 'l nd dnmuged in var lous por ts .U. Intu rro~~tiQns,IntirodtlCltO:n & ~ _ ~ ~ ~ . _ & ~ ~ ~ _ & .~ . __ . ~ ~ _ _ ~ ~ ~ _ ~ __Seed"" I. Geneeal 110>""110"" to ~Lln . ll.Uaok , __ _ _ __ __ _ _ _ _ _ - - -.-

A. Lessons Lout""" and Opinion" 011 Milling. ---- -----ll. 0,.,",,11 Err"", of ~I lnlng G.mnp"ig'"C. Rec,uiting "f Crew,.p. Ellccts 011 tog~'i,,".E. )Iiro i g Losses ALI,ib" ted I" Sub",!>, i , , " _ .See';olllL EIf"",~ of "Unillg i n Inner ZO llO _A _ G e ne ra l R es c :t io fu 3 to. Inner :Zolle M it'in ~.-- -- -~ - - - - _._ - ~ ~ - - - - - ~ - - - - - - ~ _. ~ - _ .- - - ~ - ~ - - - .. -..D. E:ITcC:l!~f I nn er Z on e i r. Ji ni ng o n C ou .l l~ rm e. rl S~ .C. ElJoFl , E 'p eo d ed i n C ' ou n t< > '_ n :l en o u, e.s.D. Efre(j~ on lr~n, S~eC!]Jind JIunl t!ons Prodllaj ,ion._E . Renehon'" Ka rea n }/ iJ J illg.

Seet~~ ~~l1~cot. of ~lilling in Ou\.,. ZOlle__ ' ._ '_. ., _III ElJ". th"""", , of Am l ) 'r i o" , " M i l le s .

, . (2) Yallgt .e it","" and Bongkong.B. X.'ll"tI~nds Ens. Ind I < ! S _C . S iD gn po l" I! a nd S Qu th e'n .4 "OWl' .D. P~.i60 klnnds:

, (I) Pnlau Islnnds,( 2) R n. b" OJ I E n ';""g d ' I ~.B. Sta~;"'i"_l Su_;v._""_: nn . ,10 , , , , , Iomoh 1.1'0 iii A" ---, - _ -- - - - - - - - _ _ -._Z - " " ' o s of S.".tcgi" M ' " Il ' . cine rea _OI lC) (uodor M pa ro k " ", .., .) ( pr ep " d b Inlng lacknde of the J:npane"" ,.,_:: - .--- -- - - - --- re YTWMtiot h .4F). '. . ",,,,Plt"_(In ner

VJ

THE OFFENSIVE MINE LAYING CAMPAIGN AGAINSJAPANPART I-INTRODUCTIONThi s report b,.jves a sumruary und nvulnati uu of

t he. oflensive mina layjllg attack uguinst; the Ju p-uuese duriua Worlc11VtLl' II: TIle eampuign (lX-tended tht"o~hout most of the war. Dm'iJlg thist ime, mines were Iaid frol11 the homeland of Japanto the most remote areas of her acquired empire,claiming lnrndreds of ship cnsuulti es nud produc-jug widespread 'interference with her water-bomecommerce, Mine h,yjng" was nccoffi lllished byAWed submarines, surface vessels, nnd aircraft.Partioubrr emphus is i s placed 011 t he lat ter, sincetheir use in this Will' wus most extensive and pro-duced such remarkable results,

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PART II~ENERAL SUMMARY ANDACCOMPLISHMENTS

This miue J ay i ll g nttuck 01 1 the . Inner Zoneupproximut ely [2,000 mines and required onlpercent oi tim Twenty-first Bomb I' Oonunntotal ~ffol' t, OL,t of 1,; ;;29 B--2lJ mining' mis0.111)'15 IIircraft, fni led to return, a loss 0'( less1percent. Prince KOlloye evaluated the aerial miningtack in the lute stages of the war as huvingan ova r-u ll economic e ffect comparable to the bing and iccndiary raids of the remain iug !l4..cent of the Twenl y-first Bumher Command''fOt'L~ Leading .hpnllese industrinli ts andperial J apanese Nava l Officers admit that theing was one 0'( the most sai-ious problems wfaced Jupan dtldllg the closing mcnths of confItis s ign iieant that, in the 5 months prior ten d of 11ostil it ies, mines sank or du mngedshipping than ~yother agent includingm:.l1:ine or direct nil' nttaek by both ArmyNaval forces."2. Ouse ZonePIjOl' t o the finn 1 mining blockade of J npun

ccnt inuing with it, another widesprend 111 ini"!:" c:unpa ign was conducted in (he m1!lI1lY'SZone. Thi~ uctuek C0!11mel1tl 'oel ' cornbatun Lves se I s .Of these 9 destroyers, .. submnrlues and :3Gauxil-j;LI"Y craft were sunk. .

1. 1n1te1' ZoneMore th all 1 ,2 .50,000 tom! of sh ipp ing was sunk

or damnged during the last 5 monthsof U10 wnrwhen the B-29s of the Twenty-fi rsb Bomber Com-mand executed ron aerial mining blitil ngn.illste.nelIlY port s of the Inne r Zona and the Shimonosek iStraits, the lut ter being II. most \'ihl n~t!ll"y forJupunese wutlll"-bol"ne CIl1l1JHCl"Cll. :Mining hl'oughtabout a virtunl blockade of these Btrn-it.s and ItIIUl0 importnart indush-iul ports on tbe JapaneseInland Sen. In addition, it caused a marked ove r-all decrease in enemy SlllJJpjng IInd severe lyhundienpped movements of tho Jupuneso Fl eet.

'Oomillet'; quotnttons of this fintl O{I'.I stntamulJu.'kf1f.l- ln Iho Iext hy an ,jJsLNi~ll;(") IlIiI)' bu (uurue ellli of ["",[ Jr.

1 CONFlDENTl


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ommenced , port s such as Rangoou und Hai -were ral'ely used by large ships. Other

sueh (IS Shnugillr i, Houg Kong, Talmo. Bang-Smgnpono. Balikpnpun, und umbnyn were

closed to enemy ~hipping by the threates. Enemv bases such as Pa lau, P suang andl!g were Iib~lldoneo.lshortly after, and largely

o f, mining, GBile r al Chsnnn ult has creel-ing of the YlUlgfze River und . por t s 011 theCoast with ha"jug been one of the majorcon tribu ting to the f u ilure of the JapnueseinSourh China in HI!4. Testimonies of

s e mi li tar y offi cial s support thi s c la im."of lhc !lIIemy's failure to supply and reinforceops in Burmn can be aHribu ted to the Per-mining of ports in Burma Siam, }.L11ay, andthe outhwes t Paci fi c Thea te r, +9 wpn.t "t lt cwern mined by o .irc rd t. T his effort greatlyd with . Japanese at tempts to exp lo it theandsEast Indies and supply their troops illea. It is estizna t ed tha t 01;0Pereen t of the"h i pping losses in the Nath~rlan'l Enstwere caused by mines ,"three submnrins mine layil lg missions inresulted directly in more than g 1"enemya nd 2 1" d an :! !lg lld . T his mioing caused

nce rn to the Japanese and forced them illstanees to chn.nge.standard shipping" routesden~ ~bn.1Jowareas to shipping., thereby I!X-uddi t'onal vessel s to d irect torpedo a ttack:een sud~ce laid mine f ields in the vicinit j-Sol0r .n0~ lslAruls sank four destroyers an~lSlgnific:rnUy with the logistic supply o.ttroops m t ha La rea du r ing the closi ngo f tlI a cnmpa ign there..ied submarina or surface vessel was lostelnymg, an d oat of 3,231 aircraf t mininonly 40 planes f ll iled to return. gthis widespread campaign in the Outer

etted more th:m 250,000 t ons of shippinganotb!l[" 520,000 Lons dllllUlged. . Even

I lp o rt a. n twas th e fuet to nt vi tILl ship ill~ampered in its movementB.an! de:r perI ods mnging from IL d l Ly 0 t t- . r ' 11 '0 . 0 aer-all Campaigl~dering the entire mining CUJllplligninbothef!LlldOuter Zones !L total f .Imines were. I .d . 0 nell.l:y 25,000

_Ill agrunst th~ Japane~e..2

Q. f these, 21,a89 were u ,i rc l"a .!t type laid da rmg4,700 sorties with!1 l oss of bu~ 5~ pI.Mes .. The ef-f e and thecost wer e but 1 1< 1 1 I D 1 > 1gnifican t portionill ...J.o:fthe o ve r- all w ar e1iort a gJ ll ll st ..apan ; still t.heresults were propor t iQl l lL t e ly V61"y high,IIIconsidering the nCGomplishments of the minI!luy ing eampaigu , i t shou ld be r ecognized tha t shiplosses are but incidental to the pnmary objeJ)tsof III mine IV 1 1 iob nrc to delay a nd disrupt tImenemy's sbippiJ lg, disorganize his mar it ime supplysystem, nn d ~hereby deprive him of essentinJ mill.tfltj' and economic material s. These l{!, tt er ef fect .' !CilJlIlOL be eVlLluatod directly as they are too closelyintegrated with results from illother forms of ~t-tank on transportation und shipping. Sufficientinf orruarion i s ava il ab le , however " to ind icate tha tmining made a significant centribution towardsthis and,Another objoot of mining is to force upon the

Ii ll !!mythe mi li ta ry and economic burden of ma in .raining n defense against it . This may requiremincs 'Weeping or clearance, mine spotting, specialtreatment n.nd modi fica tion of sh ips, and variousmeasures to prevent minelilying operatdon S. TheenlUllY's concern for these matters was demon-stntted by his degaussing of naval vessels andauxiliaries even though handicapped by ser ioussbortllges of e iect ri en .l equ ipment and teehniea lp.erson.lleJ. In tha latter part of the war, anti-Il~cra~. guns were moved from important indus-triul el~lIlSt~ l?cll,tions where they strengthened de -fens~ In illUllng target~Lrcas. * As a lust resortn~lmbe.rsof scientific and technicnJ personnel werecliverted f;"Om other lVol'k to that of the develop-ment of mm e countermeasures. B tho d f theWill d fe ~ .. . y . en 0__ '. e .n se n gn ln st m Jn lI lg W a s given top priorityover ?ll otber defense rne!tsm:es in Japan ..*T h is S II TVe yof th . ~t h e mtrung campaign has servedo tecmp.nsize the fact tb!lt mining does not com-pe Wltb hut is . '" .d t b' - a vel)' euecl;ive complement to.iree Ill! IDllfllle. !lnd air att ~l_ .._strategic b .b ..., -II=. on s luPPl l1g .o.nd. .om mg of ports . d . - d '1and road tr ..' , ill us " rleS" n.n rru. anapOl. tatlOn sys'~- T' ulsuccess of tl .. . ........9. 1.\e epec tac lJ; r'1e TIlllll.Ilg opnt>n.t d..P !Ht of 'lIn . ~, lOllS Ul"lUg the latter. " G wal" was nnd bt

.0 mlnmg on the enemy' s mil i-

t ary ll I1 .d economic suppl ies i s necessari ly o ;n it tedfr om. such data, which fact se rves t< ; emphasize ~.cconservative nature of tll is evaJuatl.On HI compuri-son with tll.llt o:f OtJUll: fOl lns of n.Ltack.The most significllnt conclusion to be. dJ::~wn

:from the analysis of the minelnying open:lOllsIlgn;inst Japan is that this type of wlll::fars lSa;:teconomical and effective means of atttlckwg a mart-time nat ion, * with the added implication ~lat boththe offensive' Rutl defensive aspects of mine war-fal'e shou ld be "ive .n sa rious conside ra tiou in futureplanning for t h e securi ty of the Unit ed States.No review of the mine laying campaigns in

World War II would be complete without ~e.n-bion of the high degL-ee of co?perution' that.e:g"~Tstedbetween the Navy and the A.il : Forces_. The Nav?des igned, supp lied , and se rv iced the r nmes ; t~le .AllForces laid most of them. Close and continuousliaison betwel l Il sereices was necessary. The re-sults of the enthe mine attack on Japan !\1"B a. tribute to the successful coordination that. wasachieved.'"

ABSTRACT OF STATEMENTS SUPPORT-ING GENERAL SUMMARY PART 11(N 0CB.-Mol"6 detailed statem6nts as obtru.ned in

inteL'l.ogations arogiven inAppendix A)(1) Prince Konoye said thet the~e'rinJ.~g

of J .ap! ll lcse vessels and the B..c29 lienal : 1 1 1 1 l mg ofJu;panese harbors wareequally as effective as theB-2!) attacks on Japanese industry in the closingstages of the war when all food supplies ~d eriti-cal materials were prevented f rom reaching theJapanese home islands. lIe stnte~ tImt the. airb lockade became inc reas ingly eJl 'e ct l\ 'e ns UnitedScn .tCS!L irc rn .ft wer e able to reach, bo th by day andby night, to the China Coast, He further statedtha t los ses :hom aer ial mining WG1'e not ,\S great asfrom di rect air attllck; neverthel ess, this t-YPGofnerialat tack was dec isive in rendering the fe \" survlvjng vcssel s us~lass_ (NOTE: Actual ship lossesf rom m. incs were consideril.bly g["e~ter tlUlll thosefrom direct ai.l llttack dlU"ing this pe,rlod.)

Advance Echelon,Far En.st Ail Force, Tokyo5 October 1945

(2)~It wn.s not only the bombing 01 Ilctoriesthn.t defeated us; it ";lIS the b loc ka .de wluch de-

prived us of essen lin 1 raw materi als-aluminuand coat" Takashi Komatsu

Nippon Steel Tube Co., Tquoted in LIFE Magazin

(3) "Hisauobu Terai , president of NYKping Co., Japnn's biggest, also blamed foodraw material shortages for defeat lind addedin the war's last months 'the proportions ofping sunl: W~1"81 by sub, (jby bombs, 1'2 by min(NOTE: The proportions of sinkings .!lre. n~rect but are mdicative of the impression shiofficials reeeived.) Hisnnobu Tern.i

NY K Shipping 00 -quoted in LIFE Ma(4) ''We agree that tbe mine wnr:flllecondu

by American planes during the. Greater EastWnr produced a, very great strategical efi'e:ct.ticulm ..y, after we lost Snip~, tha lUl?e.raida of B-29s which used Saipan nod Tinibases, coup led wi th the bombing raids 00 thsi sl ands , quick ly r educed our ncar potentielhasten cd theend of the war,"

Statement iSSLIedby confeof ,J npan ese mine experts(I"(!len~ed by TISSBS)_

(5) "The result of B-20 mining WIlS so efagainst the shipping that it eventually sta [vcountry, I think you probably could haveened the war by beginning earlier." Capt, Kyuzo Tamura, IJNUSSBS No. 26 (22 October(6 ) "The mines were not effect i"~ enough

cide the war, but it CU1ll10t be deuiad tbat theone of the main CJlUSIlS of our defeat."Comdr. Sehurol'udllllUlDu,USSBS No. 226 (27 October

(7) "For example, one of the scn.lan~ "' !IManchuria to Nii gata; the AmerIcan Al l" F ogon to lay mines ill this Ilrea about :MM:ch,July tll!l.J3.PIUl.I'SB lmd succeeded in m~\ '1l1g~per cent of the goods from Manchuna to Ithat they 113.d pltlilmnlon. Inhe Izu asupply situntion was ba(l from thefu'st of 1

Maj. Gen. TlI tsuhiko Tu.knshimU SES No. 475 (24 No"embsr(8) "The Allied sen-miningcn.rnpaign

barl )ss ed the opcrn tiOllS of the .J IIpnnese ACONFIDEN


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Harbour remained blocked through lackne weepi ng faciliti S; ships wer lost and thewooden hips became neces sa ry ; the morale1 's c re w s n n d t he mo ra le of t hn t roop 0)) boa re i

- c l el l lr i o[ 'l i ed."Ext met l"OUJ report 0 fComdr . J. , , i ]bbet t, RNI n te ll ig e nce O f f ic e r,East Indies turion

"In Burma re triction of the u e of teele U L o O O by mining gn va a great effect tog hti n . ...forces. mnl l transport enpaciry of

en v sel could by no means satisfy til de-o r o peratio n :fo rC es .. *. Tl;c 10 ofund harbor closure nEected greatly the CUI': ti li tar y opera tion on land and the expor t o fImportan t goods as tuuesten . l end. and micaan e l and were hardl y renlized.':

JIIplllle5e Nn l' ll l C l ll Dm ,mdBnngkokIn te rroga tion byLt. J. F. exter, Is"R1 January 19*6

) "The If t of the mines was very se rious.ularly ~he d~3 suffered by hip en I'~nd I avmg ~lI~por. AmOl l g the Inrgerd a ll lR ! !e tl d ll l' mg the L ime I '11'0 there wereE, HYUG_\_, and the hospital hip HI.A l\1AR .At I t 10 1cas 'III( p erhap s asl IS 15 or Ie ships and 2, 0" 3 s m al l s hi pslink .. . "

Vice Adm, , hil!e!'l1 Fukullo.lllU. JJNU, 'R No . ! iO ~ ( il .D ~ c eJ Jl bc L ' 1 ! J+ .j )

) In peak i ng o-f the IUISIlOCI'SSu IJ'C hi " ,1]JILneS!!In .ina UJ 10.]4. the Commar di G14th Au : F' I ng en-oree (Gen ,,,I Cl I nnr 1t) J.that' J ' .. 'LI I,. In llS 0PUlIOII ; "A rial minim ,. t1y respon i~le for the long dCJll;l~'I~~~ed to a ta tical lef t f ' Uc ea 01 ie J apt ll 1e . .. "~F CBI E"nlu:,tioll Boanleport No. ' " (10 December 104+. )

'The Helldquartel of the J ' .Fleet found Arne .: ILpnue se Chill'land disa 1a'0" . l~ef~lImines :ex tr cme ly e f f e! l -.. ~ ~,alnesclll'neclb ~ . 1pluue could cl-n ~f Y IJ . SUl g, ~u=lLpmt 'Qralollg "de. Together with U ' PC) If)O il tbe J ap ' ll Ie se 81 ' I~ mencan ned "I ut-, jjPpll1 r r out es th b l o k .

ucla of Shllnghai by Americuu mine greatly in-t dared with tl~e tl9.llspOl'tntion of mlll lpnW eL'l lIIdWill' upplies from hunuhai to AmoJ, Foochow,Hong KOI1g, Formosa and 1:I1I.inll111 lund."

Th e J a pl L l1 I l. SaNu.YI11Liaison Ollke(Cll i l ln)(20 D e cembc l' 1 9 45 )

(13) "The Upper Y:nllglze wus closed for longperiods during tb summer and lid] of 1944. ByIDLe pring 19*5 , al l metal' hulled hips were heldnt hanghai because of the el' it icalmine situation,Ti le mi li tar y si tua tion was . ..r eu tly a ffected by

t h e m i ll ' especially t he JUP (l I1 s e d r iv into SouthChinn . ' I' ll Japll11esc were unable to end troopsand aquipmun up or down the Yangtze. Move-ment of troops and material were .onfiued 1" 0the inadequate rail fncilities.: 1 .. 11s up p ly f romhnnghai nud the Yal1"tze valley urea wasail'ected * * *" .

0 , 1 1 ) 1 ; , HOlld'lJapanese NIl .1 'ai Attache,Nank-ingIn te rroga tion No, 3NavTechJap dated I !) D e c emb er 1 94 5

14) Rear Admiral Mat uzaki (Chi f of Strdfecond outhern Expeditionary Fleet) e timnte~that 40 percent of the s hip pi ng 1 0 es ill the Neth.-rlands East Indies wer caused by submarines~,Opercent by mines, and 20 p en \e l; t b y u ir m" ,j ,f t'Most of the larue sll' 'I ' .I .," ..ps III t lC urea had alreadyJeen.slunk by t he t im e aircru.:EtbCglll1 to o pe rn te inCOil. I (ern bl e n umbel 'S .

R


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CHINA

, ."u.k

z'b

Mill,

O F FE N SIV E M rN E LA Y IN G C AM P AIG NA GA IN ST J AP AN

()(:TOBER.I'N2 TO AUGUST, 1945[OUTED 81'

AIRCRAFT, SUBMARINES.,. , SIJRFACE VESSEL.S


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T O T A L D / W T O N N A G E E N T E R I N G J A P A N E S E I N D U S T R I A L P O R T SR I N G 1 0 0 a B - M I N E L A Y I N G

II

8

"

PART III-OFFENSIVE .MINE LAYING-" HISTORICAL sUMMARY, 3, Mi,ne Layitlg Executed b y A i. r( ;f 'a ft , S 1. ma r ine s , and S1~rfa( ; eCraftDuring the course of tll campaign mines w

111il1 by the nited ta .Army and AlliedForces, a well 1\ by Unit ta tes ll av!~ll~i, ['Cuxface vessels, 1\11dsubmarines. .All 11 1 d tanrines were pl' pared under he .sup rvi jonUnited ares naval technical persOImel,W!lI:fal'e officers di ree ed , 0[' collaborated inplanning and ro; l lClLt ion of all op>ll"lltions. Theoperation between personnel o:fthe different nt ate and forei zn erl.-plojt economicnlly the richresOW1'Cesof her new territory, More than 7 mil-li on tons of Ja .pall l! e ihipping were employed inthis essential efl'ol't. These h ips were under con -stu!).t danger, first from All ied subm:ni lles , thenfrom a. ircraft, and Jinn lly from sea mine whichmenaced every important harbor and s a laneavailable to them.1. Prep,mttionsDuring 1942the Navy bad made e:.-Cel ls ie pt'eI-arnLions Tor a coordinated strategic mil le attackon the Japanese ou ter defense zone. Mtnes de-si sned and produced by the Bureau 0: Ordnancea:; ;' ing 1941und 1942were dispatched toMine De-pots established throughout the Pacific and inAustralia, India, and China. These depot w~J:e,st lvl feLl largely by personnel trained at the MineWl l.1' fan School in Yorktown, Virginja , and IJ .t he ava l Ori IDa.nceLabora tory in WashingtonD. C. Seve.ral fu tu re Mine Wldllre Op l'ntionOfficers were assigned cluty in London to stu iy atLlle Admil 'nlty and report on th experience all li ledby the Briti 11in the war against ermany.2. Objectives of OfJemive Mining Cam-

pa ignTbB objectives of this mining cumpaign were

to disorganize Ule auamy maritime supply systemdeny him safe ports ani shipping routes for thetransport of essential Will' and ecoucmic I D . L l .t l lt 1 1 11 ,to sink and damage as many of his ships u hewould expose to mine r isk and to 'im pose upon himthe mil it ary and economic burden inc ldenL to I .hestablishment and rnnintenunce of 11 mine defense.TOOH7_0-~ 9 CONFIOEN


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based in Austrnlia made extremely long cruises tothe dangerously billow waters f Ole Gulf ofThailand and the Gulf of Tonldn in the outhbilla eo. where they plsc d minefields alongJnpane e shipping routes, Submarines fromPearl II'II.l 'borconduct d similar mining operationof f t he coas t of Japan and hina. This- miningcontinued intermittently throughout the war untilII. total of65 mines had been laid during 33plltrals',Beeause cited tn tes ubm nrine w ere so profit.ably engaged ill hunting enemy ships with torpe-d o es , t he s en le of th.ah' mi.aclaying e1I'ortwas neverlar!re; but the ir act iv it ies oflered II. COil tnnt threatat a larue number of widely separated points ando presellted II.very con iderabla problem to tbeapanese. aldom have a few hundred mines en.anger~d shi~pi. ag over as large nn urea as didose Iaid d~m'" the submarine camplligll, Itbasdetermmed thht l~"" n~ ,.. a east ~I enemy ships were~' ,and 27 were damo"'ed as a X I I uJ t of this effort,JS likely that these ligures represent a bare mini.of r~~lts becal lse of incomplete reports ande proba~ili~ that many of the c.'lSllnltiesin the

laidmmefields would be attributed 0other1. Surface Vessel Mitzing C ".I. '. a71_",mg11-South PacificE nrly 19{3 marked tile start of oE sj'by surf inel en ve mm- ru:a1ll.iJle ayers , By theend of Januaa-ed States forces wers completin'" the G duJYnal camp , d th ua ., .' Ulgn an e enemy was muJrln . defi'or-tto in! hi 'g It 11 -and 'I'o a id ] re ?rcelS garrisons on that, ' 0 I!.l III s toppmg this alltivity destrlaid mines In th b'ls oyerbe USedb the II c. ~~e most likelyIToJ. . joY Ex ene~y, ~eu: mterference withed sinkin o~~~~as lIINd~catedby the oh-1 b on e Ipponese demoa eld the very night of the mine Ia . . y~sfullayinO' of mines w as f II ~' Thisdeeper penetration of tb d ~w ~y deeperthe olomon lands: ~ , ~ermJ_Dela.Ylll'sOn e ch . . s e campltl!!Il pro.illlnel after Ilnother was bI k dThe inability of tl oc esweeping forces for re~ Ie e _ n e m y to pro.Wa s s hown by th f . 1 . _ perung the IUlnedf e net WUt ou r ownound It numbe r of fialds till' sweep.States forces later mov:d i n : ~Jace wIlenI ~ , . lese areas. .ncn4.Bur1lla-First Mi ' , T _ ' 'tJe IAYtng bU. S. Aire'r.aft 'Ye niahts of22/28 Febru,tl' ',m d surillCemin I . Y 194.'3,wIJj_lethee aYlllg cQmpll . ignswere

10

UI fnll progress, the fli'st 111ymg of mines by Un'tate aircraft W!IS a compl ished, Unt il th ll t t ~ t r J dhlu~JlI.panese had been sending troops nnd SUPI~~lleto t hei r gl l, l 'l ' is ons ill Burma by ship, 1'0han l l l ! $those movements the Tentll , S, AU ilispl1! I t e r1 0 B-24s (Liberator) loaded w i t h Brit,is11m e , l e dazninst Rangoon. Shipping fell off .il1lmedin~~and from that time on few large ships ever I I It~pted t o u s~ the P~l 't , This r_nol~ced the stu.rt01It VIgorous mine laymg campnlgn on the PH1'tair forces based in India, N either Rangoon 01th ithi _""- D or!lily 0 er portWh illaircrart range w as long nfrom mines after this ini ti0.1erilee, ' l ! i l3. SouthPavific-Fil'St Aircraft Operatio'h mw~t U, S.Mitles ' ,The month following the]a,ymg of the RangooQfi~ld brought tI:e first dropping of United S t n l c . snunes ~om U~l ,ted~tl1tes aircraf t, By th is timothe Buin-Kahili region of Bougo.mvil le had b e.co~e the center of enemy resi tanee to Our cam-

puign to take the Solomons Islands, T he an-cl1.or!l~ehere w as freqnently used by enemy sup-plyslnps and naval vessels, O n the mO'hts of 20:wd ~: March the ~fety ,of thi anchorage w as~lo?nued by two IUll'J.al 1l1.111irjO'sil'ikes each COII-SlstlD b ",.vgoa out , 40Nuvy and Ma,rine Corps TBFs,~ese first n nae lay at Bou!!ain v ille W e re th eOpemng of n minin, ' ,at the closi d g C , \mp lWgn which was aimedosin ow n of enern 1 lin '

:.nese o~tposts U I the S Olom ;n~f~as, e~:r,~ ~;nd surface layers collaborated' ,. 1 . , 'the fO"mol' lay' 1U un rs crun pm gn. ',~ m '" grO lID d' ,waters while th i l1llnes lJ]_ the shallowerYn;" '. e a tor established fields o f m o or ed.......es across the deep ,result of thi 'I r u ; appl'oach channels, A s al\Ilemy W"" I~ nune aym~ a. total of at least six

"-' S 11 ps were rmn d ern, ' ,sinlriu", of "d t e,.L uis includes the, '" "eSl'oyers 'tl 'In.'' of I) th ' nnC I ie s e rIOUs d l ll ll ug '" ~0 l'S which b . 'a subsequent dir ' ecame "si tt ing ducks ' forern! , ' O ne li


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() f " Lta i ni mr r uu xim ur a r es n I ts wil.h ! ei I'ted supply of gasuline and explosives. The"I',reupon, uudel"took n sniall but enthusias t iemineg cllmpaigl.l which extended f rom the Tonkin- - - .in rha south to ihe Yuugtze 1~iver in Ol e north,g Kong und Tnkno. soon booame fuvorite tnr-for the mino la~ing plunss, Both of thesees , e .;pec in ll~ the lat ter , were used ns s tag ing

for con TOrs rlLll]lillg be tween Ihe E m p ir ut he southern Jupunesa holding>;; even minornys tllel'e represented 11 less of ruluablc ship

Tactieal 1I'fini1~g-Peilie Area.early 19+1. , as tlle Pacific Fleet began to p,Is11theeuemys island defense ring, mines beganused .Ill~re ",xtensively as tactical weapons,fi rs t l IlUI1ng .l~ be < lone expr es sly in pr6pI11.H'fo r an amplublous a tt ack wr,.;;directed againstMm"Sllill Islands in late De-r:enlbel" 1948. andJlllluary 1!M-!. Groups of 11eaVj bo~bersTarawa and Aparnana placed o"e; 100minese entrllllces to thosa four of the atolls whichto be by.pussed durillg the invasion of the

Mhzil tg o f Pallm30/31 ~Jlilcb 10M a strike occurrad which. ~ lI .l "k e d t he growing tendency toward t o w . .mnuns- This wa s th III t . 1 ..' e- ,. e 'S rmne aYlng mis-ned ont ~yUmted totes cunier ..based ail..

W3SdireCted against the !llllilll) ' strOll"',of Palau. All principal passages into a:dt IlC atoll weremil led Thir t t I'd ", . . ,y. '\\OSllPSWC!'I!up I~I the 11:u-bor , Illter to be sunk by bomb.The Dune laYll lg at Pa lu 1I denied to the eMmseof tIle }1I11bo fOl ' at lel!.st "0 d ., Y- "ays It!]u "'lISth, e : flld.ors whlch led to its;


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17, Yt1.11.gtzeMi11il~g-FQ.urfeellth AAF am].B-29s

During this period, the only other group curry-on mine laying in Asill, the Fourte nth .Airrce, had been forced by the 10 ' of _ me of itsrward airfield to limit i ts mining etrorls to theYanetze, Thi important supply l ine washams ed however, with more.than 300es being laid durin". tile fi~t 3 months of 1945.included over 100 aircraft laid driftiazwhich were dropped ups tream from suchaces asHangkow to float down onship and bargeTo complete the blockina of the Yangtze,B-29s carcied out two heavy mininginthe mouth of the r iver in March . Thisinterfered with !>hlppina b:n.llicto andom hangbai a" w II lIS in the Ynngtze i elf.

is interestiutr to note that this mining was donethe request of General Chennault , who consid-it ofsuffi.cient importance to sacrificehis ownited supplies of gasoline to re:fu.elthe B-29sstaged throurrh China for the mis ion,18, Cbin Coast ltlil1i.ll.g Undertaken by

RA.AFThe mining of other China CoIlBt ports previ-ly done by the Fourteenth Air Force WRS takenby the RAAF Catalina squadrons operatingth e direction of the Commander of the Sev-h Fleet. .As soon as bases in the Philippinese availnbla, th e squadrons were able todertake mining of t ll e China oast in addi tionII. continuation of their a tack on the Nether-nds East Indies. Thus the capture of Four-nt h ~ Force bases accomplished little for them.."Ofaras gllinina freedom from mininr-concerned. bNER ZONE CAMPAIGN

remIllluts of the Japl1nese mel'~h~nt f1ee~shuttledbuck and forth between the AsJlLtm cQntJ.nentuu(jthe home islands , r ti~atively sa:f.e f rom attack b~United Stlltessubmlll'111es r heavy bombers, M o s tf this shipping w hi h was adequate (I the t i J nto supply Japan' ne ds n : itllin. the lTUl~!' Z o n e :pn ed through the strategIc Shimonoseki Strnifl lto industr ia l por t located OLl the Inland Sc a 0 1Jnpan, Inallnutempt to blockade this watetborllecommerce and thus sevel' the Japanese lifeline totil Asiatic continent, 1 3 - - 2 9 s newly based in th eMa.rinnas now undertook an Ullprecedented sat-uration minine campaign directed at Japanesehome waters to remove these waters from the ]jo tof a reas safe for l lIlarny ships. On . the ! lpeniJ lguigltt of the minina efFort, jns t pr ior to the land-ines on Okinawa the uper for ts of the Twenty-first Bomber Command carried nearly 1,000 mag-netic and acousticmines to the Shimonoselsi Straitsand the Inland Sea , Thus, at a roo t oppormn,moment the Japanese were denied the use of S U I !Innes on which they depended heavily, both to rushreinforcements to the Ryu1.-yusand to bolst r theirhomeland for the impending invasion.This mining attack on the Inner Zone w h i c hbegan so spectacnll ldy in late March continued

until the end of the war. ~(Ol'ethan 12 000 mines:l '"lIre laid in every signi6cant channel a~d harborIn Japan and Korea. The Shiroonoseki St. raitsand all importan industrjal ports were almosteompl tely blockaded. Hund1'eds of ships weredelayed,. sl~k, or, damaged and supplies vitallyn?eded ill indu tl"lnl and p o pn l a te d sections wei 'l l~verte~ to nortlJllrn Honshu ports where much ofItj'emmned waiting to be hltuled over an alreadyover~oll.~edtransportation system to its usefuldestination,First Phase (27 M harc -2 May)-OkitlaWIlB-29s Conce.ntrate Mining A:ttack Otl Em - Supportpirc W uters-Start of Blockade TJle mirtino- cnmplci 'B th divided int - I gn ngllJ.llst the Empire w~y ~.end of M arch 1945, the c on ti nu ed o ff en - in U P I J O I . t 00f()tPhelIlS0ek.i~'.h e fhost pbasa w as p l l l . 1 l , n e de agalllst the Outer Zone by direct ub .d ' . U t i " u manna no eki braits the ' .nawa operatIOn. The Shlroo-air attack and by mme attrition, together with and the militl nN l ' aval bases of K.ure and S!lSB.bo,forward advnnce of our forces to the Phili were ~ :ned . ry pe t of emblll'katlOn at Hiros]uJlI3es and Iwo Jiron and the initiulllSSnul . p- ~ inan effort to I finawa, had forced the Japanese to wj~; :ns t , JaplU1eseavl1lunit. encangel' movem ents 0st of their J:emainjng 2000000 gl'O t aw ticulady desil-e1 to S 111 those places. It was par'

to the Inner Zon~, Here op:~ 'a:s ~f, :.nese Fleet ~ I pre"ent the sortie of the Jap-comparari velyshalJow and wel]-~1"otectedi~~Whenceit couldug1he.Shi.monos ki trait s frowina Sea, Yellow a, and the eaof J under COver of sp c l to the d fenss of Okinawaapan, the' we tern Ky u I I 'Ing was successful, S iu, 11thi s the llllO14 . the only task force which did

sor ti e, a ttempted to s lip out of t il e Lnlund Sea viuthe Bunge Suido (east of Kyushu) where U. S.units hLYin wait. It was at this time that the bat -tleship Y UTO was intercepted and sunk.Second- phase (3 Ml"y-12 Ma'J)-Indttutrial

Cmter BlockadeThe second phase, termed the "Industrial CenterBlockade" was begun on 3 May, The pmpose ofthis attack wa;;to destroy the seaborne communica-tion routes between the groat indust rial zones ofJapan by maintaining he blockade of Shirnono-seki Straits and by mining the por ts of Tokyo,Nagoya, Kobe, Osske, and the main shipping lanesof the Inland Sea, This phase marked the intro-duction of the "unsweepable" pressure mine, mostpotent undersea. weapon developed during the WILl',A. totnl of 1,422 mines of all types were used inth is phase, Shipping at. all ports began to fallrapirlly and ship sinkings and damage immediatelyincreased, Much of the shipping which formerlypassed f1. 'omKorea nnd JI:[anchuria through theShimcnoeeki Straits to industrial ports 011 the In-land ea was now diverted to northwest Honshuporta 01' to Kyushu.Third- Phase (13 May-6 JU1U1)-No'rthwestHomhlt-Kyusl:m BlockadeThe third phase began on 13 May . Itwas thepurpose of this attack to blockade the bulk of

enemy shipping moving from the Asiatic mainlandto Japan by continuing the blockade of the Shi-monoseki St raits and by mining all the major11a1'bo1"8f northwest Honshu and Kyushu.. A. to-tal of 1,313 pressure, magnetic, and acoustic mineswere chopped. Thls pha-se saw the introductionof another "unsweepable" mine, the low-frequencyacoust ic , which was used for the f irst t ime to con-found the Japanese in their feverish attempts todevelep mine eouatermensnres. Shipping 0011-einued to decrease in Shimonoseki Straits and theindust rial por ts. There was a. corre pending slightrise in shipping in the northwest Honshu and Ky-ushu port is, but the newly laid mines resulted inmany casual ties among ships which had been sentto these ports as the lesser of two eYi l s . .F07~rth Phase (7 [une-B J1~ly)-l1ttemifiedNor thwes t Homhl l-Kyruhtl BlockadeThe fourth pha eb egan on 7 Juna and consiste Iof ILsimilar but greatly intensified attack. Au ef-

for t was made to complete the blockade owest Honshu and Kyushu bymining the secund wrt iary harbors ill these areas, andmaintain blockade of Shimonoseki Straitspr imlt ry ports of northwest Honshu and KTh important, port system of Kobe-Osckalso mined repeatedly during the fourth phtotal of 3,542 mines of all types were laidexpansion of nctivity, During this timlosses accumulated .:apidly in all minedhipping began to drop ol I in the northweshu and KYllshu ports , while in the ShimStrait s and in the industr ia l por ts the sapproached a complete blockade.In conjunction with this fourth phas

PB4Y-2 (Privateer) aircraft of Fleet AOne based on Okinawa conducted anmining attack amlinst shipping op ratingYel low Sea. around t ile southern coast oBetween 10 June and 1 July, these planes186 mines inthe archipelago nlong the souof Korea, forcing sh.ipping to abandonaround the many islands in the area andout to clear water where i t was vulnerablr ect attack. This mining finally eliminateee her the movement of ship of ove r 1,0Fifth phase' (9 J1tly--15 A11-KlIst)Blockadehe fifth phase carried the blockade toin tr enemy shipping at every possible pointing all the port of Korea while maintainblockade of himonoseki traits and thnorthwest Honshu-Kjushu area. .A.to tal

mines was dropped in target areas. Theyincontinued shipping losses and a fa llinraffic in all ports. The closing days offound Japan ringed with ports polluted wimines. Shipping through th himonosekiand inimportant industrial ports had beento a trickle. The Japanese were not; ablel l . 1 l y of thei r ahipping lanes eff icient ly,f r rsd to take abnormally high losses rathtop completely, Their ships used the divepor ts on nor thwes Honshu and Kyushudesperate mea ure to ~t supplies to the mHowever even th is accompli shed li tt le asited inland -ansportation fucil it ies prevendelivery of the necessary food and materiaheavily populated industrial rcgious on thSea. This mining also prevented the use

15 CONFIDE


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o;f the 22 principal me,-clmnt mnr ine shipyards ,d rep aiTITork on dumaged sil lEll ing far exceededlimited co-pacity 01 tII0&! fe w unmilled Y O - I 'd s .

s a result, uny subsrnntial damage to merchantssels was the eqlli l~nlellt of s inking, s ince its useas denied the Japanese fot tha duration of theThese accumulat ed results of the mining emu"ign lef t Japan littlfl hope of cont inuing t im warr long. Resultant shortage of coal, oil, salt andod contr ibuted so completely to paca lysing in-tllut shortly Worn surrandnr I~adillg in-s tcialists indirectly inimmed the nril i tar is ts thatdust ry cou ld not cont inue . Th.ey est ima ted fur-er iiJat7,OOO,OOOJnpnnese wpuld have starved toif the war ll(ld continued nnothl)).year,

The eflti~eB-29 I1t tnck on the J~pnnesl' l Innll tZono had used 12,135 mines, Itraquired only l1i2~sorties rapr~s~ntingbut ,~,7pe rcen t of the T'\'e~~.first Bomber Command's total c1fort, Adlnir~1Nimitz in his cOll.llJllmdution of the Gxccueion o:fth~campaign, has describecl the res~1ts (IS being ph~ .110meniLI. Pl'incol{onoye hasestimated that in tllufin al mont ,hs of t im wa l' til e mining a tto.ck W I l !squallyas elIective as tIm bombing o:fJ npRnesa in,dustry which occupied the other 94.3 P B l" C en t 0 1the B-29 c:f fo !"~ . J1 complete evalua tion of 1 \ 1 1 in.telligence nvailable ~n the resultsof the minell\J' ingleads to the conc lusion that t im over- al l contr ibu,tioll to the Will' e fi 'o. t was most worth while il.ll~thnt it wns accompl i shed wibha minimum expendi .t u r e of effort.

16

plunning of n cnmpui gn, but also during t lie couof its execution, and in eva II I at ing the r esul ts a fwards.A mine Ir ly ing campaign is generally of a s

tegie nature, It is therefore important formining off icer (0 know the relative economicmi li t ary impor t!LI1ce of the prospect! 1'8 targeThe volume of shipping, the size of tIle ships!e n [Iture of tilei!' clu'go n . r!l Ill! fnctsw hie ll h, sign i fi cnnce , and must be care fu lly studiednnnIyzed i n the planning srages of a campaign.Mille laying opsrati ons orll.depel ident upon

geogt"lIphy and oceanography of (he tlLlget aupon the status of the C! lBlny 's counte rmeasureand espec iu lly upon the disposition of the en~yshipping as it vnr-ias throughout the attaAetial photogruphic reconnaissance is an imtall t source 0 f this information, ince the sucattained with the use of mi nes varies inverswith the ability of the Ilnll.1l1:l' to dispose of thcontjnu illg (let a i led nnd uccurat e intell igenceeJlll.my minacountarmensnres is a most imporrelement In t he successful prosecution of 11 mineampaign.Much of the informntion needed in mine p

n ing an d op em!' ion s ell u be uequired d u r ill g ptime. In this connection. itwoul d be desirablIULI'e files ~et up in t he Chief of avnl Operatiofol' aU potentin I mining targets. Informatioshould be gilthe tedOil the economic import!of ports and cargoes, size and number of shhn ndle(l ut each por t, t erminal fnci l i ti as, locut ioof channels, water depths and currents, charaof bottom unci similar facts, These .1utn shobe the object of continuous pence time investig,atand mensurmnent. A .n H vniluble information cce!ning the riln'lJlopmellt of mine countermeasureby potential enemies shou lei also be obtained}J enee time,It is important th:l.t l'clT dose liaison be es

lished nnd maintained in the future between mwarfare orgunizatiens and all intelligence sourIII implamont ing thi s I in ison, the fo llowing funruantnl steps should be accomplished: ,

I, PLANN.INGPART IV-WAR LESSONS AND CO:M:MENTS

1 7 CONFLDliNTJA

1, Need f 0 1 " A de qlM J e P l ep a ra l i0 11One of the b igges t handicaps in t lHll l1 in il lg cum-

pni g!1agn insl Jnpnn was the lack of adequn te prep-!m.tion in pence time, MOllY aspects of modernmille warfare were new. The possibilily of usinginfluence mines against enemy waterborne com-merce 01. ' naval fOI 'Cc .s lrud llot been fully lnvesti-gated., nor had the use 01 ' aircmft, to drop suchmines been sm:i.ously considered, The (lBI'

ing is mentioned only boca use it serves to demon-sh'ate iJlIl need of !waiding n I'epctitioll of thiserrol" in the postwnr period.

2 , I 11 J 1? o r ta ' l1 , ce o f IutelligenoThe i rnpor L J L O . C ( J of udeq ua te i1 to11ience to the

success of a mine laying campaign cannot br overemphlls iz{ld, TJ. lis WlIS recognized by mine wurfaro officers in every theater of the wa r. Reli ableintell igence is essential not only for lIie ol"igiJ\ld


16/70

((L) InteUigence requirements, defined ill ~Bpeeific a mann r as practicable, should be formu-and tran mitted to intelligence officers whoable t . ( ) obtnin the required information. Thesequiremen s should be red d pe riodical! .(b) Intelligence received hould be By tem-ically collected, evaluated and tudied no onlyIIview 0 as ssing the imelin of the gen-nl mine warfnrs progrrun, but also :for the pur-se of informing intelligence ollie 1"- of th spe-fic . d ata which may be locking and which is(c) lOOe warfare information which can beickly read lind easily understood should bemndeailable to in tell igence oll ie I ' so a to providewith the bit ic fundflmentnJs necessary forelligent observa ion and Ilil'ectivereporting,

3. e e d. o f E a .r ty Deoision OILMilliltg Pro-gram. '

!n order thut the mine requirement of tIm oper-g force may be fnllilled with a reasonable de-of success ~t.i essential that prior to orearly

.IL.war, a de'?ISloll. b~made regarding the desir.h(;y of a major mrnmg cllillpni!!IJ.only then canbe prepared which wi l l provide "for the

ssary loaistics, In the last few months of thewith Jap!.u the Twenty-first Bomber Com-n~ was ~ble and willinn to devote a sti ll Iarzerion of 1 e1fort to mine laying, but suffici:nte . toeks were not available, The basic reasonthis lack of stocks was that the decision to carrysuch a large scale attnck wa not made untilrtly before the actual mining at uek begaIy..n view,of the many other def ini~~tic COIDmltmen ill the Pacific, tblll'e was cy and reasorutble reluctance to mve rni .;lllss ',. b .,. nes wlearypt'lonty III oth production and sllipping,E s ti 7 l1 . a te so f M i n e s R e q u ir e d .roughout the minin . . cnmplligns in all the-s there w~ a t~ndency to UJldeI'e. !l ti .Jnatehaer of aerial mUles required t . . .ti Thi -.., 0 rnma I. gn'ent on. s wa due partiaUy t I k fintelligence on the efEecLiven~sloC f JO upto-ep' apanesemg mellSUres., and partial ly to lack of reeo'"n of the fact that Il, relnt]velysmall pe . t -mines dro "".1 b .' [cen agecharm Pl',~ Y urcraft fall in to theannals, The lllJpottan(; lesson to be le,necessnriJy, that all estimates should.b arucdtt L e more, ra leI' nut more complete iniol'matibe u.vailable on the looaf f onIon 0 enemy chan-

nels, the nceuracy of planting, and the abilit;v of!~enemy to execute COlUlt61'm~l1cSU1'e, Also, It is e s .sential tllat ~~prienced mule wnrfare ofl icel 'l i ~ava ilnble to interpret and anulyze enemy i J l t e l l i .gene in order to l'llCOJlllllBnd t he mos t eCOI10llJic,. ff t l0 1 i st ribution of the mimng e or,II, OPERAnONS1, Generala. A~m.o8tToo Little Too Late

Despite the success of the mining campaign, (blnttack was very nearly' too lit tle--too late." hHeady every a re a o ff en si 1 '6mining would have pro-c1LICedreater result if it could have begun at allenrliar date und on a laL'ger scale. As previou hs ta ed, the delay was due to the lack of ear ly devei.opment and eo.dy basic thought on the olIens il 'epossibilities of mine war fare, This type of war.~IL~ wa new, an~ had toundergo a period of p r o v omg I t,sGlf before It was accepted. It is fair to S({l.ieh~w~ver, that after the early stlCMSS(lS of offensil':JUllun"', theater commanders used this weapon rusoon as bases and suitable mines became available..The development , production, and supply of=,es themselves was pushed with particular vigor~ur~g the ll l,t termonths of the war and the logis -tics m t~s regard were outstanding consideringthehandlCl tp at the s tart . As a result , the ruiningcrunplIlgn progressed with II tempo which par.alleled the o'Ter-uJl prosecu~ion of the war Itgni ruiJapan, The natura of mining attack . ch h .ever that' t ld '1, IS SU , ow, .' .i CO U nava preceded other offensiTeuction to a greater extent than it did s Li thiway would h d' M1C III ,t '1: ave mi l e a still greater contribut ieaa me war. .b Ai1'S .,.. upe 1'l(H >tfly an d A ,lI 'ia Z u L 'A erllil .. 1" 1fL'liM t l l ! J ~ n gity to til l1U!1eaJ'lng did not requh'e air snperior-e extent of diIU r, Most of th ~ee.mg complete cont rol D f t b etrue contI'ol f ethll1Jn~lg was done at night when

D ean'w db thenemy and b.-ien'I.' as on tful, and bo, .L J IIU' 'l'rll; h d f(:Lewan. This condit' ' . u some fl 'eeJOIll 0Lhanmost oil'e' I on m ad e mine laying eas ierI nSlVeaeti I 'ielp when othenvise o~. t allowed aircraft tobeen restricted F theIr operntion5 might haveh . '01 exad II'Offells' . ample, RAAF eatatinnS. Ive U s e s till. .Inlllelll.ye('!lll th S ' s they wore ffect.ve n Stl' h e outhwe~t p i 1 : iOIlSsOWed th . ~ ac C . T ll ei r operaa mInel . d~venwben COnlplet . aYtng cun be nccomplisbeIt call'eu" 'II Urnsuggests t l , . t . penonty is laelcinfJ'.TlIiB,na mUle 1 . th18 aYlllgcan be done WI

limited resources when other types of ofl'ell'Sivenit-action might be less practicable,'I'he facts lead to LWO conclusions:

(1) A arral mine warfare CIIn be undertsk IIeven if a nation finda it self almost s tr ipped ofn , i J : power a WIlS the United States after PearlHarbor. In this case, mine layillg may be aneffective and economical means of thwHrtinga seaborne offensive by Illl enemy power.(2) A nation should not be lull d into a. s ense of false security over tile slizht prospectof attack from another nation weak in ail'power, since the latte:r might well make a veryeffective milling attack upon the stronge rpower.2. Ta~ticat Aspeota , T a c lJ i (Ja~M in t ing

The bulk of the mining again t the Japanese wasof a st rategic nature, There were, however , var i-ous mille Iaying ope rations which were ex cutedfor tactical reasons . They were, for ti le most pru:: t,successful in accompl ish ing thei r puxpo e, par-icularly in connection with amphibious and otheroperations in which it WIl,S desired to interferetemporarily with the free movement of eIlemyships. The fol lowing brie:! , descr ip tions of someof the tact ical operations exempli fy cases of typi -cal employment,

1. Solmnon.sls'la,nds.-In eady 1943surface-ruining was employed tactically to interfere withenemy naval ships which were making quick foraysinto t.he Solomons a rea to hurass tour forces orsupply thei r own. Destroyer mine layers plantedmoored mines in some of the more important chan-nels which might be used by the Japanese withthe result that several enemy destroyers and sup-ply vessels were sunk. Thesa mine fields helpeddiscourage the To1.. 'YoExpre_ "whiah had beensuch anuisancs to our troops,

2, Rangoon, BwrllUJ,.-In July of 1943 sev-eral enemy supply ships had sneaked up the r iverto Rangoon. Inorder to trap them so titlle tileYcould later be attacked and sunk wjth deliberationmines were immediately dropped into the riverchannel. The mining Wll,s uccessful , the shipswere prevented Doomsail ing for several days butbad weather unfortunately. prevented subsequentail" attack upon the ships before they left,

3. Marska1l18lands.-In JllDual'Y 1944 theMarshal l Islands were mined in support. of t lle

move into tha~ area, Some atol ls were b1JYthe amphibious act ion. Mines werein four of the most important of h to deuse to the Japanese. Dummy mines wereinto he atolls which were to be capturedto prevent disclosure of intentions to theLittle nemy shipping ventured into the asequently but it is po ibla that the minefered with any aHemp to supply the isolari ons on the by-passed atoll .

4. Palau, AtQll.-On 30 and 31 Matcprior to nited tates landings 0. Hollanorth ewGuinea, carrier aircraf t, a tt ackedwith mines and bombs in order to reducetiven ss as a ba e from which the Japaneselaunch a. poss ib le counterat tack , The atj:sisted essentially of first mining all exit pto preven the escape of enemy ships thenbombing attack in which all the trappedwere either sunk or beached and finally theof the anchorage and bombing of ' ins tallntprevent further use of the atoll by enemyThe operations were completely uccessfPalau wa abandoned as It forward enemshortly afterwards, However, in ord r topossible use during tile nited States moMOl 'Omi and the Marianas, Palau wa againin June IIl1d Jnly by RA.AF Oatalinas,

5. T'l'llk and, Wol&ri.-Truk andlike Palau were mined in support of the aions move Ilgll-ins Hollandia. They \vere cshipping for nearly Il- month and the enem110 ea or air counterattacks from them.6, Shim.o1Wsoki Straita,-By fur tbetactical minin a ffort of the Will' was xecutehe himonoseki traits were mined in cotion with the amphibious move azaiust Othe end of March and in arly April 191nirernft, of the Twentieth Air F o t , C G dropped1 500 mines in this important pass. !re betwJupanese Inland en a nd the East hinapurpose was to prevent the Japanese Flee'sortying throuah the traits and speedingdefeu.~e of Okinawa under cover of westeushu, In this aim the mininz was uccessthe only task force which did ol'tie was fosneak out of the Inland ell via the Bungoa to Kyusllll) where nited tat nnvnconld lll lel'ccpt i t. Itwas at this tune tbaUleship YA1IIATO was sllllk. The minhimono eki not only had to.ctical significancit n.lso offered lllldlsputable proof that lar l O C 1 1 1 t e d wi th mine wllda!'eex"hy ,1 factor of 10 0 eorl :v .i[l the W~. nn d

t tl !f np ~e d t o c op e w i th th e p '" !lb le .l ll s o f bD~ie "0 -In the influence fie!ds 01S ll ipo n '. ., .d . . -, lme ueSlgllr nme c~un tl l rl " Il l !aS u l e s. which h ud b ee ll g"reatJg lected S illce W o rld 1 Var I. A t tlw om O ~ . t" Y. . I . =< , U/,WIl0.0 c ear-cut concept Ion of c>peT utiolJal. .in either eNO 01" I'he Bmn., u (,f a ,!"Iqlllre". . . . ,~, . [f noncet he result timt mllrh of 1he endy 'v . k 'd -, . I .'. 01' pro--eu Wit l ou t s po c if ic direcliflll It W I.I ..... lIS no " u.nlilla yses of opemtlf )luti requirements f ." .' . . .. 01 " IlU lIe sle rnaueanrl mcluded IJI (lil"llctil 'es f C "0 ]'.' . !Urn ! .' \Olo11 I"l thut I nm e d ev e lo pm en t re ". eiv ]

'. - . . - i!( prop!lr' 1 l 1uUl l c e. TrUlYtlift[tu'lties thol had Ul"'I~bnI. ."~ . 1.l1ring

d e'1 el oll e, ] f in d u se d, p ,n ti cu ln l" ly in g ro un d mines,w b i ch r e q l l i T e d maximum dnmnging e.ffect.. ' 1 ' 1 1 ; : ; ;roq U I l"emeut. eonti IIties and t here is need f()). furtherreseurch 1'0,,"" [ '(1dovl 'lopi ng or adnlll' il1g sti II moreP" w.f["fnl !IX_[)lnsi ves,

c. Need to I" , ;mpliflCllf.ion,of Pjepal'()lio!1.B xp erten ee d u r i n g 1 "I 1. ew ar jndicut es 11need fo r

simplil'itntioll of mille preparation. Th i s i. ilesir-able iI order to slun- ten j he time nece :> Io 'y fw/ Iheussambly lind testing of minas and to red lice theneed for highly special ized techn ic ians to ser vicethem. During the war the design of these intri-care weapons proceeded at such ,I fust rate thatrn a t ters o f si 1 11plificatiou hnd to begh7en s ec on da r yconsi (\el,.ti on. A s II resul t some of the mines )"e-quired eunsidernble servicing andspeeinl utrentionin the .Jield. Conditious at f01"1I'1l I'd bases oftenm ade such CUTe difficult.In future mine des ign nJI assembly, testing, nndadjustment of mines should be mude ne simple aspossible. Mines should be so designed that tlley'CI,I\ be issued to forward b ase sas co mp le te n ss em -blies thnt become ready ammunition wjth the in-sertion of II buttery an d detonator, and the adjust-mont of diuls to obta in the desired firing seusi-t iv ity, sh ip count, delayed arming. aud sterili zersettings.5. Coordination and Liaiso1~a. Oool.'{li fl l. ltio" with Other Types of A ttack

Generally speaking,. the OV


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c : 01 i .e ns ;1 '< ' Jli11ing-lts Relalhm '0_ ub -marine Afff.l~~. Direot Ail " J Itac{,-.(I;I!dStra-tegic .Hi" Bombing

In eompnring oflensive JI1 iue Inyillg to otherfo rms of a tt ack it shou ld beconside red as II com-plementary effort ruther thun a competitor of fillyother means. "T il le . l ay ing f il ls a n impo rt an "Itpill n w et! ba 1IIcell attack on the w a til. rhom e co m-merce I lJId nava l fo rces of :1 nat ion. It s poss ib il i-ties vllry from a degree of IIUiS(UlCfl value to avir tual blockade such as ex:i.~ted in 1 1 1 8 himonosekitrn its nn d the im port an t in d ustd nI pOI!S ofJapllll, Itcan general ly be nssnmed thnt minel ay ing i s more economical in both equ ipment undper sonnel thanothe r means of achieving compnra-b le r esul ts and should ther ef ore be cons ider ed illtbe over -a ll p lan of ,Hhlek on any locality depend-t upon wn.t" 'rborne traffic,d. Importance of Oentl'ali2ed Coordination. byONa

At the begill.lling of the war a Mine \Varialeeetion was esta blished in the 0 Olee of the Chiefr Xova] 0 peru t io ns f or tbepurpose o t coordina t-ng all mine warfare activiti es, The necessity andtal im portance of thi s CBn rolhced coordinn t ions been e mp ha si ze d b y the experienca of the min-campaign. By allulyting cperationel require-it was possible to guide BuO.'(] ill deter-the types of mines needed, t he ir m l at iv e

ior it ie s, and the q u an ti ti es a nd distribution de-ired. CNO controlled the release (If mines tor viea use, thus insuring tile coordi 0ated intra.

of new mines in all theaters a nd a ," O id in < >ema ture int roduct ion and consequen t compt"O:ise of a mine in nny one thaater, The collectiond dissemination of operational informllt ion andelligence among all . heaters WIIS also effectedthat ~perat~ons in each area profited by Ilxperi~

guined ill others. Close supllrvis.ion WIISaintained o"er t he trnining and distribution of

w a r fn . rl l personnel, tInts prol'iding nil com.w ith lbe most capable and experiencedning experts availnble, AlWy Air Force lini!;onf icer" formed nn integral patt of the ol 'gnnhn.ion, 'This general coordi nation of the variollses of miDI !. IVf ldl l .J :1l has Deen an imporbLllt fac-

or 111the oVe1'all success .of the min;ng cHmpaign.e. i1nny-Na:uy Ooop.lt1 'ation

The cooperation between personnel 0 f the Ul)il~dAxmy Iln~Navy and Io,'e ign ! i < . > 1 'v i c e s i l l the

logistio S I I P P I l I ' t and operlJ. tionnJ d~I 'ecti;oll of i ' ] 1 ~, in un p n i"ll W>IS ~x em p l u I'Y IU n , 1 l th ellt~l.inuung CI.., .:f l ".1 t 'ibtltl!il much 1;0 tIm success 0 tIe OVel'.ul!nne con I I . rn t ta ok , E~1 )I ll 'i .e 11celll'jJ:tg [ ,IC .war ; l1Clcat ,ed tllntI ... ( jr~,tive larrresCllle Iter'tal mi ll e L I l. Y l ll gw" "t. H~ : rm.~ I i l ! ' " 0 . ' - .~ '11"ellrded ont by l(Jug 1't111gelJOmbel'~, In th{ll'll~ifil'cnmpu ig n most of this o w n s undertaken by th~Unil'ed S t. ut es . A .rmy . 4 , . 1 1 ' Forces, SUppOl'ted il lSoutl:tenst Asia nnd the South west Pacif ic by til!Royal Ah Fon:e, and the ,Royal Aus~r~Ha.l l A ilForce, lUnch of the plnnning and lOglst lCS, 1Ow ,eve r was rlltTied out by Naval oflicers and by Navyo rg n 'n il Kl ti on s w o r ki ng i n close liaison with t["Air Forces,In ge l le t 'a l " m in ing r eq u ir ed d e fi ni te knowledg!of the amploymenf of ships and of (:,heir chamcler

isties a s m ille targets. Because of its t hr e! l, t I Q:f1:iendly ,shipping Il.S will as enemy, mi ll e lay inghad to be coordina t ed with p os si bl e f ut ure N al 'B lmovements, Th e p roblem of sweeping mines W~!a. N.avy responsibil i ty which had to be consideredcarefully in its relation to mine laying. On t il!other hand, Inrge scal e mine laying ope)!utionswere directly dependent upon the Air Forces fortheir execution and formed part of t he il , s l ir a tegi !n~tn.f' Illll Oil Welt'hs lhe lJOogliJ.O01 !i~Cllt'lty, '" _ '

2 6

nr. RESULTS OF MINE ATTACK1. Evalllat im~ of Sbips Sm"k .a11dDamaged

b 'Y M.i1lCSIt is d iHicult to determine nn uccurnte flgure for

t.1!enumber 0 : 1 ' ships sunk and dumnged by ralnes,Most of fhe Jilpanese data have been burned, Theollicial l is ts prepated by the various agencies intlle TIll] to o States IIaJ:Y considerably in accordancewith the limitld;iOllS of thei !' sour ces and tha s tand-nrrls of validity set upus proof of sinking in eachinstance, Itis probable tlll1t even the most. lib.em! figures nre incomplete !IS muny ships h~vebeen SUlik or damaged without u.ny record beingmade of eitllllI' the sinking OL the cause, Oftenmines have 110t been suspected in au area and thesinkings were credited to some other callOOS, Infact, some eflicin 1Jnpansse opin ion has suggestedthnt ships sunk by mines have probebly boon at-tributad, .in muny cases, to other agents s,llc11 astorpedoes.According to a compilation of the data avail-

nble, more than 6 5 . 0 , . 0 . 0 . 0 tons of Japn.nllse shippinghllve been cl 'ed. iw d os sunk by mines. In additionto this, rnore than 1 , 2 5 . 0 , . 0 . 0 . 0 tons have beendamaged.It is estimated th,at the totals fo r mine casualties

will be increased by at least 1.0 t o 15 pel' cent whenf inal evnJuation is completed, Itis probe bls thutthe f inal total figure will exceed 2 , . 0 . 0 . 0 , . 0 . 0 . 0 tons withronghly 6 7 5 , . 0 . 0 0 tons b ei ng S IL l 1knnd t he remain derdamaged.2. Bvahla#m~ of Sh. ip Dama .geStatistics furnished by tIle Jnpan~e show that

th e tim " re qu ired fo r rep airin g la;r~ ships dum-nged b y U ni te d. States mines wIls95 days (aver -age for ~nhips) and that required for small shipswus 70. days (llvolmge for 16 ships), Towanls thBend of the war, the limi ted IlUlnbm" o f lil')' dm:k~I lBd the SGRt 'dty 0 f mllterials for ell:~eting l 'ell>lil 'spt'oCIl1(1~da serious sillintio!l ill w hich m an y dlun"gad shIps could not be llclmi tt ecl to r ep n il ' f nd lities, SUcl\ ship~were efFec~iI'ely sunk iusofnr nsusefulness 1.0 tIle .Japanese IIUS concemed. Th",best clntn nllllihble shows that n t l cn s l( l7 : i. O OOtons 0 dlllnog~d emmy "hipping WM in I hi s CHIldilion fIt llle end of thl! war, Tllis figure llddedto oller 6 5 0 . , 0 0 0 . tOllS aduu U y SILl lkgive s th" totolo f m ore thun 1 , 0 . 0 . 0 , . 0 . 0 0 . tOllS whi ch might. be C


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1 , E ne my COllT l te rmeas / l / ' 6 sB.\' the end of the war, lh" ,JUp.lUle!iI' luul de"

fairly ,'Ife.:!ire SWQ~P~ frn- "U Initetlmines """eLfl nih Ill"m!'1ie m illP uml till'

l lI1 ) mine . On t il l' . . Ihn hUI1I1there wns unf fi ei eu t q ua m ity "o f ~\n'i!pillg e q ui pm en t II'-II il-W Id us a result they were poorly prllplLredmeet a hH'!!l"s 01 '1 '1 0w i, d ~ , lere ClIP'OIlSto p!lSil 1m Ilkelllly veriollde{l J'Ui s ~morder til r .each rbe indllst rial 'lW' . YI 11f J ' " pOjJtI utedJ"n~


22/70

as closely related cpernt ions clu~ed geM.I"IIUymine warfare , I 'ersonneIBH"llg~d in eitherI.l~dto be fumil in r wi t h the other )1 1 ordertheir job proper ty , Personnel plan-mine laying had to consider both the cnemy~Wied possibi lities unci responsibilit ies relat-to the sweeping of the mines lnid, imilarlysweeping personnel were reqllil'ed to be fa-r with ths opera ionul and technical chmnc-rie s of mines in orde r to S' ''eep them IIfrcc.iuce extonsiva 1:1e"eJol)Lllen~ot !.lIed mine with i ts inlfnellce firing mechanismsade modem mine laying and mine sweepingintem e pendent th Ill! ever, it is i11}JOt't:ll1 ti ll the futnra the two opeintions beconsideredmsepnrabla elements of mine warfare.Y"'QiHing-OfficBrsollioers who participated in mil le warfareions duriag World 1Vnr II were with fewions Resen-e. officers. ThlS \V'1l> especiai lyuf those officers engaged in offensive aerinlluring. This g:i'OIlP was made up of a sma IIt ion of mme l'I'a.rnll.ll experts , nearly all ofhave now left the service. Itis undesirable

t hot tho J u h . i L " C of )l1i n C l . w urfn re ~h~llid del!il~upon such n gt~Up of lughly s~cCJIII:zecl . o m ~ ~1 11 v ie w o f the Impo~tnHceassluu:ed by tIns f o ! l ,of I l tt nck : Regular ofhce.L"should beco~le gel1er~l~b .m i ii n r with th e p lA ~ I II ng lU:d ope ra tlOntt Ln~[J~Luf mine lilylJlg" and irs l~laLl.f:m t o o l: l1 e1 " typ~ Iut[:lcks Oilsllipping:. Ofhc?rs ~ttendlt~g sCutt["!II] " O " c s e s p e c i u Uy SilOlllcil"eC(lle 11 l s tl 'Uct l on in mi ,-0 S Iimi .~wllrfm'e and its uses. ome premllnltty f~llliliIU'Jz::ttiulln tim subject should be given at U,Service AC;lfiem.ies and the various fUght sch0ll16. Trai"i1Jg-EnJisted PersonnelThe enlisted mineman's rating wa s e sl nbl i] ;l i,t1m'ing the war as direct resul t s f insistence n ' ~ amining activitieshi the Fleet unci at adlIlUCe.jbases. " " I T nst numbers of minemen wore trained IItho N IlI'I! I n:fine Wn r fa re School, Yorktown" Vo-for the highly specialized work IJdmine testing nn~assembly. It i s e ss en tia l I;h at the minemnll's I'll.illg be preserved in the postwar period to provittia nuclensof wiOll-tl'allletltechnicillns for nJ.inetl.lo't.ing ami assembly, lind also tb'at th.eMine ' i V u J " f a nSCl1001continue to function in tmining enligroJpersonnel as well as officers for specialized I \ ' o ninmining, .

30

PART V-CONCLUSIONS AND RECOMMENDATIONSof 15 B-29 aircraft, Broken down, thissen ts abou t 4 5 'a bi CIISU a]t ies for e nc h alost 01 '20ships sunk for aach.aircraff lost .

Ih. Airernft, mine laying was introduc'iV-orId War nand proved to be genern.l lyr im' toother means of Iaying mines . Minesbe considered, to ge th er w ith bombs, as impair force weapons,i.ince a mine luying campaign is clolaced to the entire wa r strategy, mine plshould be considered as an integral portover-all wu' plans.[: Mine laying. as n general rule, shoulmencewith 0 large in. it il ll attack nnd be coby frequen.t modemte size attacks l"~l:hel"tcnsional Iarge scale attacks. Inaddition, tInying should be distributed. over a widearea in order to put the maxrmum burdenenemy's mille clearance forces.k. Mini.ng experience in the var ious,,"cnemlly ver ified the principle tha t much;alue of 11now weapon l ies in its surpriseduction and large scale usc 'before ti le enedevelop countermeasures or adopt alteCOUL"sesof ac ti on.I, Much of he success of t lie aerial mingcampuigu can be nttributed to the highof cooperation batween the various A.irwhich laid the mines and the NIlVYwhichoped, supplied, and serviced thel1l.\.notl~lIpor tant factor in its success was the coordexercised by tile central mine WI,Ir fnre orgaJin the O f fi ce o f the Chief of a \ ': 11O p e m t i

2. Ret;Q1:I~me11d.atioll;s Sttnz.m;a,rizeaa. 'I'hnt 11 prcgram be undertnken foopmentof TIlineeountermeasures .and new

to be completed at the end o: ff ive years.b. TI~(l t the. mine countermeasure pshould receive hlgb priority. It should

don" the following l ines :.'" 1. Prevention of mine laying b

t ion uud dest ruct ion or diversion of craft cmines.

31 CONFIDE

1. CQ1lCt'llsi01~S S1I!1nm.a1"izeaa. Offensive mining (especially byait-craft) isa u effective an~l aconomicul means o f a tt nc k in gen6my slUIJping and disrupting his mnrit ime com-

nierce.b. Qfi'enl iive mining should be cons idered asa complementary efi'or t (not a competi toi ) to sub-maeine torpedo attacks and dirBct air attacks OJ]shipping and to sW."ategicbombing of indnstriesand port areas, Its relrltive jmportan~e ill com-pa rison with other forms o.f .at t~c.k ~Vlll be de-pendent entirely upon ootistl llg Slunt. l?nS; undersome conditions, itmlty be the most sni tahle formo:f attack.c. Inland waterwnys !lJ.C particularly vulner-able to aerial mining.d. Mine warfare bas always bean -eonsideredItS !L contest between mine designers 011 one sideand countermeasuresexperts on the other. Ex-perience during the last few months of the w arhas indicated, however , that mines can be made sodifficult to sweep that practical countermeasurescannot be developed. For the time being, there-fore the side taking the offensive in n mine layingcall1~aign can, by judicious employment of the dif-ferent t.ypes of mine fir ing devices , achieve a t re-meudeus Il.dvl1ntnge over an epemy. Blockadeconditions CIlJl be produced if sufficieut mines arelaid. c. In consideration of the destructive possibil-it ies of offensive mine laying against ll. maritimenation, grea t stre ss should be placed upon the de -velopment of countermeasures to ddeat such anattack.f. On ehe !L\1el"l lge one ship ensualty resultedfrom every 20 to 25 mines laid. Tins ratio variedconsiderably with the locnlity, the amount o:fshiptraffic, and the typs of mine. Fower mines pllrCU!3Unlty were required in confined chllJiIleis, inarMS where traffic wns heavy, and when new mineswere introduced.

g. Milling data from the Inner Zone showth Rt 6 70 ship casualti es were obtained with a loss


23/70

e 'l 'hn t iI Id 'l ct ri u u tion i n th e opel"lltiolluj'ia e r e d '; ,: tk s o f m i IJ()$ 1\ I" cl t l ie f un du, 1 1 ()J IIals 0 r ~ :Ih l" in g b e .. iv en to n illce !'S a t th e Al'my ulIL1"tIi:.ht ,rh~!1ls lind f:1 in h t o p er ar iom r] tl,,~'ll" ,' . - , , 1 11 11centQI'S.f. Thut u cJlJoulIl.entH.!'Y ~ilUi ])0 1I1utle of I Im in e w n rf ur e enmpuign ag 'Illlst Jap ltn fo !"

. . . 1 - f - il '. II~pose~ of IJlst.L'UCtiOll ant. 'a~II H1I"li'latl~J1 af SIll"vipersonnel with the 5h'utegl(!: and tuetlclll em]1, . IQiIII an t {ff 1l1.1n mg. '.' g. T hnt re.nlis0c dl"i!L mines be elllploY~d i]0)111WIU'exercises III .01"(Ie]"to d eve l ( 'I ll IIIi ne la,\'illprocedures [LIlli doctrine 3S w~lllls to te.~t tbe e a 'clancy of mine c le a ra nce me a su r es ,h. 'fhnt offensive m ini u o- plans be drol111

-fOI" n.ttuc:ldng p o t e n L i . 1 1 l enemies and t h a t t h e , 1 1l ec c ion o f in te ll ig en ce . u ec es sa ry f or impleJl lmll~:'sueh plans be progressive find co n tinuous dUI'il~p ea ce ti m e. l If in i n g P Ian s shou ld be closely coonI'n~t.e.d 'W i t h ove r- a ll Wilt" plans and be iIltegrntJwith them.-PART 1. SHIP CASUALTY sUMMARY

L. Tllil~ l?ostwnl' mille stoclrs be mnint!lil1cd flihn mll~ suflieisnt fwalltity to ini till te a m in ill" empargl.l 11; a cc o rd a nc e w i th lllining plans.? Th n .t . f ur ] l? st w n ~ planning consid('rtl~illr0 0 . , g ll 'e l, 1 t o. ollnttmg a s uf li ci an t I)OIt J".Ol ' of li tt -, L Notes 01~ Stt'IM1r#lf"y mid List of Japanesela.eglc.A.u: F O J : " < ) e t. o mine layingae may b e nil;essa .! .1 ' to lmt l ll t e and m aintain a m inrnc Cl l l 1 1 p l l i g u Ship Camalties to Allied Mil1CSagainst !lily enem . 1 . '" S . ] L' I b -tion ' , 'Y emp uymg wa te r tl"fLnsllOli[ T he J'apanesa hlp Cilsml ly . is t nas een com -ion. 'I _'I 11 '1 bl 1, .,..,_. Wk' . . pi eu. 'h'om II SOllfCC3 uvn I a e to Iue "H.We . ar-t . ' ThatdefensivelJlallsbeclrllwllllpforcoull.f:He S ectio n o 'f the O lllce of t lHI 'Chief of NavalC lmel lS ti re s t o bead t d i I . 0 . I .. f . bt' da ttack b -'. . ,op e m t ie event of a JllI~~ per~tions, t contmus 111 ormation O 'alIt!! .'fhese il i l~ 1. !Lunchedaga inst the United Stull!:; from the mlJ1)erOUS sources listed ill the legendfrom i~ll011 -t 1 1 lc lu d e l : In n s f or d iv er si on of tnlflil gi v en b elow . It is reco gn ized that these so urces urelifJll SlllJl~~\nnr. slnplJllI'''' centers, lind cOllsitien L o f v ary in g l" e1 in bi1 il.y a nd fo r th is rel!50n Ol e de -

. rail and t e g iven to the associated problom, , I IgL"ee 011've ri fi e at i on is s ho w n for each Clltry by in -, mo or huns[ t t' .. - . JUl' It lOll. {lie' lt ing the source (s),This li st hns been checked both dll :OllologicaUyaud nlphnbeticull j. in ")ltiar to' nlimlnute apparentduplieut ions . 11 is possible, tIC"",eVIIL", thnt thereare some double elltl."ies in enses w here the som eJ up u ne se c ha ra ct er 111J1~' I ruve been h',\ nsluted intodissiruihu: Engli 'Bll equiV,\]ellt:s, UlllVOL' whereslight diserepnncias between sources as to date ,locution Ortonnage were present,

A.ll caSlllllties hll\'e lmen listed, where known.l iven ill t .hnsecuses ill which tIle samo slli p WtlSilltlllaged by 11 1illes on successive oc(;nSiOIlS or {hulI-a g ed ,m el s ll bs eq l l1 'u ti y s un k .. In m0 1s t i ns tn nc l' s knowl i tonnage f lgnres UL'eJistcd. 'r110S(~ figu 1'lllS folltlll'ed by Ih ~ lettel' "e"

2. Development of d c , c i < ' e ; , uud sr~leillsIn cut ill! and dest ruyi n g m ines on tbe SM

< -

s, n~","I"p"'''!I (If new (''-II.lipmen[ lindhn~qut '" . .' f o r sw . . e pi u g I!Iin es w hi ...h "p~I',;lt!l UII

11


24/70

aged in the Inner l ind Outer Zones , a nd it is uponthese tha t the . !i rruxes ill parentheses in the tonnagecolumn ere based.Two totals for the 11 mnla ry have been indicated:IINet Total, which i bll d on known tonnages,with the ships whose timatsd tonnages are basedon average shown be low the known figures inparenthes . a nd a Grand Total, whi ch is the sumof the known totals and es timo.ted totals based on.0reraees. Its to benot ed that t onnages for Naval

, ,,'",mary oj Japan"". 8hip ca.ualtiu 10Allied ",InuOOTER ZONl!: OABUALTIl!:8

35 CONF IDENT

~IlDOJ18Zmg(I)G(ll3I2(I)1(J)3jIJ(P'i >(: I)Z!(WR 'W( iJ(~lI1e p3q )233J21(I)I(J)3712)tnII(02U1(3)2l2l


25/70

pART II_INTERROGATIONSno.m"""l,'d-OW DJlIlIlL~tl ' I 'ornl ~lL\1L - _ _ ~ ~ ~ ' ~ ' - - - - - ~ _ : ~ = T - - - - - - ' I - : = = : : ~ - - - - - - - I ~ '-'un"'" s'oun " Nil"'''''' 'Pon,mgn NUI"bN '1'111' 11tu cllell e.:ffrllct from iJ,t'(>,Togn,1on, weI'V

N'W1b< T0"' '' ' olsh',, , ' o"blp.\ "r"hl, ,, r .\ r I'ff' \. '$b l,, , __ ~~----------selecl"" rl'Oll! n 1IUII,)el'.O (I erent sources. 'I ' . . p,," R" ..... _._ ...... __ .. _ __ __ . 1lIl 2.1,~ , 67D (~) ~,~&) 1 ~ J eolllp"I'L~tl1' , , 1 ' some of the Iu.t~lIwllls mild Withn,Jin Bay _ ,_..... 1 ~[O) : : : . := :=:c.: : : := :=:____: ' '0,2 i ' 1 m " " " flwts indi 'ales thnr t ,b int l 'I 'ognlio))' Jllil t

_~ 2 2.623 \ e * , ~2'1 .07 2 "" ' r - ; : : ' i ) e cOllsillel'ed with l'esel'l'u.tiells.Total. Onlet Z orw ._ __~ _ ' ~ I . I.!I\/~ (00,,000) (Nl \ II,(:m) (21 1 ) . .. - - -" - ...... -... WJ II The data on the Inner Zone i p;enerlLlly moreIl>"NEII Z01'-'E CASU,wrIES aCt:ul'!l.t~ lind relinbl han thut from the Outer________'--:- -._::~:.:,-:-- -----,----I------I--I---;--- Zene. Thiswnsduetuthe fact that themilling

Iltppl,__ . ... __ __..... _._.~ ... ._ ...... .. __ .. .. _ ---'''. -...... .... t f 1 ~ \ : l l (~l opl 'I ' l ILlOnR there were mOl'e recent und the col-FuIn.lnl< a- Ka:mt!u .. _ . _ . _ , .__ ,? I~,314 1.337 d ) (k ~ h l~ ) ~1ectioll of intotlilatinn more cent rulized. 10 pa rts~ ; : ~ ; ~ ; ~ = = ~ ~ - ~ : - = :: = J , ' = : : ' ~ ;= + = ~ ~ : = 1 : ; : : : f ~ l ' ~ : : ; , ; ; , ~ : ~ ; : ,% ~ ~ ~ ~ ,f ~ : i B : : : : ~ ; J~s _ _ : _ _ ~ = : - -. - - .. - .- - - - - .- . .. - - .. .. . 'i !~~ ~ ~:~ ~ ,~:~ It ~'fact. '----- - ...... _--,-.... (6) llZ,lIOO) (0) I~ It is (lollsidel'ed, however, ha till of the in-=J' !r_:_-::=:::-~:;=::::::.~~:~~~-=:~::::::...~~~ . r~~ :::::::::' ' :-~_~:::::~ ~ !:~ 1 II . b l "lilllIlolo__ __. __ _. ., .. __.. _ .VOI ....... _ ..... ~......... (~l (~,,~,/ (~,l ~tel'l'ogations taken togetllel' gll'e II rell ona e plC-~~". _ m. __" _ , .. _.um. 3 1 17,~;1 1 0 - 3 8 , ; ; ; M ) l H ~ ' 2 ) ~ :l1 tu l 'p of the i-esult of the mining eampnign.Kwr a.." App._ __ --', --.... n:~52 : : : : . = :: : . . . . _ . . . _ _ ( ~ ) (t~l (~I, Section I-G81wral Reactio1lS of Japa1U!seK ut (~J ~i:~) l~ J ~ to Mine Atta&k~!'~~: '" 00 '" , r,1Il1 ( i) ~ W ~ J ~ ; ) ~N '_ , a . . _ _ _ . . - - . . . . : ' - - . . ~ : . _ . . . . . _ _ . , ~_ . . . : : . . ~ . : : : : : : : : : " I~ I ' ) : ::='.(~.::): I ~ l ) ': 1 A. LC8S0lf i Learned and 0"illi011 011 Jiining~~F~~~_:==: __:_:._:::::::._:::.::.::::_ ''''_ ., M' '. - ~1 ) r4.170 2 3:416 :3~: ~ [f ~ The following represents the concensus of_________ _ .. _ _ r ( k g ) : : : : : : : : . : : : : : : : : : : : : ( : ) & 1: ~l (1.I~: opinion of all Japanese mine expem as presented by= = : . . .. . .: : : = - - = : : : :: : : :: _ : : ~ _ : - : .: = : _ : : . : :. : . :: . , . _ _ (I) (2,00II) (lJ ,1 1 1Captain Tamura and obtained a"[ 3 USSBS Confer..-T-----i."ij. HOI --.. ........ I_ ~ = , ~ , , ~ j , , : ~. ~ . ~ . : :. : . : , : . : . . .. . _ : : . - . : . : : . : . ~ ~ : : = = : : = . . . . ~ 3 ~ . . _ . . . . . . . _ _ . . . " : - . ' 1 8 _ _ ( : ) . . ; ; ~ :~ ; t i ) ~ ence by Comdr. Moo re r, USN.~=:.:.:~~~~ .. , : .. _ .. : = . : : = : : . . : ~ ~ ~ : : : : : : : : : : j : : : : : : : f r : ~ : : : : : : : : : : ~ : : : : : ~ ; ~ ~ : , ~ J 1, (}en8l'al o pinio n .;u ~\&lI 22 (I) (2.!OIl) (I) u 'We ag re e tbl tL the m in e W ' IH 'f Il l' con-&bJm_kl-W"" .. _..... .. f i : H i g l l " - "" ' " 12.4.. (f h m : : J : l ) 1 ~ ) l~ ducted by Axnericl1ll planes dUl'lI1g the greaterOouthw .. , "..... ___ _. __ _ __.. 4 ( k ~ ~ : : : : : : : : ~ ~ :: : :~ ~ ~ ; ~ . ( .\ ) ( f J : ~ ~ l I~~) r~ En>;1 Asia Wnl' produced 0 vel'l! .IJreat strut; yicalT.kyu.__.___._ _ ..__ __ _. .._. m , i , ( ~ : : ) ( ~ ) h , e , l ! p ( ' t . Parriculuvty, after we lost S. .. .P AJ.~ theT nmp-O""""'- .. _.. _. __ __ ... 1.'1J1 ( h ( ~ : ~ ) (f) ~~ mille l l lyiTlg raids ~fB-lI.9s which used AIPAN~ = ~ : . ., . .m ; . :: : :: : :: : :: : :: = = : : : :: : :: : :: : .: : :: : :: : : " ' " 2 100 _-"_'._' 1.11&7 (~) ( ~ ~ i M \ ; h ! i) u,. QlIO TINl ~ II base, cou]; led wi h the bombing' " . . . . - . _ < '-i7:i!2 ''''''''--ii .....2lj.7;j j" Iff 1 0 ' , : raid Oil the home island quickly reduced ow' warf f i)~ 13'1-~ .(2:!OIlJ (I) ~ IlOte'1l tial lid haetened. the end of t l,q war.

: . l l (IMoo) 'l7D,OO Ifill ----- -- I :!l~' . . n o b, a \ , 2 0 3 (,ar - ..- ",___ (!is ) (t3 t~ ) ~ ) (,M "I'hut IS to S l l Y , whello-_.9 eg on toNcl ",,,,I Zl.!IiO) ',"23 '5'l ...... '55 r.t.' "AIP \'" for mi f . t____ -- ' ... __ .... h .. .. ~ . ~" " - - f " " " - . . (30) ' i ~ ' & \ 6 ) (00) 1 1 f t 11 Il ~ 10 L~ II, U base or nnne war are ngnrnG_d lDaL~ _ _ ~ : : r M J j_ . . _ . . ~ ~ ~ - l J 3 I I ~I I~ ur muin isluruls they til'~t i'lltel'l'ltpted ('()JJwlIIfli-

_ _ _ _ _ _ _ _ _ _ _ ._ . _ - -_ -_ _ _ . _ -. _ . _ . _ . _ - -_ ! _ _ _ ::_ 3 16 1~ 1~ 1 -- - - - . . . . . . ( 1 1 3 ) (~~~lli:h (~:I~ ntio'IJ.~in tA,' /.\'LAYD 'Ell ."i1e(l afld thel! btl....1 li8, m -- -- - -- : -- - --I I J i , l J ~ . . .-----!.- __J_=~j_ _ _ : 4 . ~ j l ~ ' . : 2 i ! : ' , ~ < 6 3 ~ = ~ ' ~ , I ) ~ ~ ~ i ~ ~mung Ihe JAP.LV ,'Iff L "orl~ I1wy cut Oill' (0/11-llU!lliaanOll.' ( /l td ow' food I til d /"(I'll! mutrriaZ (fI'ICI'Yo t1w C(Jllti'llC'nt. 1'11('mil le ! I' lv 'f (/ l' t' ( IQIIPf"c l ", i lh

lie b om bi ng r aid .s pl'dVI'IJt~d lilil ' I l t i f i i l iu (J o w ; 1 1 ' 1 1 1 :trl'lIytlt (mel compl l (' l! l n~illifle,' om' JIl l/ fi ll to tilwt"lIf ,,! tordog W I ~ () (I/)01lll01l til em."Tbis >l1I(Ce.'3S'IlS IIItuined hy till' liSp of)lP IS not , 'e1 'Y we ll d eve10p'n(I.~ ditfit'lIlt 10,/n.1I lip a defense- Otb l'\vi ebelielTed tlmt efl'ectiVI l plllns could btll'e OOOhI COllUter Ine attacks,

3. f I 'cctegi 0. 1 le,~" 'ol l an d opiniona, 'In yj w of the oml it io ll e xi

the time it is I1dmitted that the concentrntinlnttll 'k _tl'ength on th Il1lljOl' hlll1 (ll'S of tlL.\ND EA to S(WeI' otlr lines of communinmllo tc Irid the lIIovement of 0111'lll\\'ulW!lll ""1'9 ,will/b7" IlI,d / f!N,/i , / . 'Thi is p

CONFIDENT


26/70

larly true of 'H!MON EKI TRAIT, l:IlROH T h I : . A B 1 " , ruld the 0 .\JL-\. .KOBE Area .

b. "~Uthough the selection of the INL~ ND .E.J. areu for conduct ing mine warfare.;~te~l'('tjye.:1 tated 8001'e. jt hould b e realizedp ,11 cuttUlg of tmn port routes between JAf and the co ntin enr by conductillg mine Will" 1 1 1 '6 ut the V I IX IOU port on the JAPAN "EA andill onthern KOREA - uld .,'" ..: - w ou hnv been even moreell.ec",Ve. Tbi' .'. . - ,prooeed in fro ispru:l::icu~]y true b eesu e sh ip sanese L I gds illtbe contlnellt to till! main Jap-an Were forced h th b .ace to chi 1 1 . . yell rnanne men-se nff t h : f~ w esin heshi ll low pa:rt of the

olf the C hinese _ a~, T he effect of millingroute f rom tl - eOllStthll1ld lIDportant points on tbeould al so be ~elt. u em Men to the homelando. 'It i VllM!' '" tiarfare 1 ''] enec ITIl to conduct mineon II arc", a 'o J 'be .mn l 'l ;n . . ..t "'tr . lIS P ble f rom the~----.; 0 S 010 the mine - .of the opponent, SWeepmg capac.

4. Tecn'llical Batt? Lmine laying lry B-1!!l~ e e 0 7l ,! lGild opin-a. "In . it~ were ab le toS~~ :v~ th~ fac t that t il e Jap.al due to Am' Illlnes as 1 eatch ma -or}can carels 'em on land no ad re ill dl'oj)ping'lD()7!.:etJ,ut, lor za:r;:e c()U~tl!1'11tea!fUI'e could

rcity o/8hip" and boa! techmca11 ' iJ8ouNics andb P" .. ~C!Ples and mecllnnj,srns1. The 'P 1h1e e t ' . 'e. mine may be Baid to !On 01 the p1'fJa ul'e.

i1lfl technicu.l event < ' - I c~n8t~tu.te all. epoch_In ' 11!lnc 1iJa"*recent years va . "are.- , 110u COU ... 'perInlented with, nnd ' DL.lle.s have ex.of mines (influen~nnn"eIiected pecial typebeen employed in . ac t 'l aes l ) . fThose.which hadtw hn-. ., War are be lo ~J~es-the n C O l l S t i c ' . onged tcmugnetic pdnciple. AlL! prHlClple and themodel s of these Ware in lough llew types andent through - '. proc of dev Ii vunatiollS in e op.ton, the p7oeticaJ, a lie ,;I'U 'tufe nnd ae.1J1'etJ!fUren c O : ": ;c t , a tum . of ~hange8 illy wai tIle m~8t d' um unt,! 1 I 1 t i p 8 un dw application of d~~:UlOd . de v e loPed ; :g u~ Utequest ion of how ~i 1 Y J hout bring_~to being, il,I!kil l! 1 ld~ m l l y havei,l ind61!{1 UJort / i ' l t ap pbcatio'l1 an d2 t T/ ; !y O f adml.rato /lo ;.q-t ~: ~;~ {i c( J. z _apPlicati:n_"niktona;ion b- , a.~ ~ (u Jtion ilet""'n'~ 01y rep t l tUJe itl,fl;u _ -''''''''''011

- e l < e e an d Me38

pl' inciple 0 / (jompo n-nd d et o1 ta bio ll '1 ' 1 / l1r1i IJ/i. t8 e0~ ~These several methods, too, ' In all 'IIS~ ~he ped cti~n of . uchctlnlly employed to a sun ila. ' b.tve~.evlces how th . r u pC1 'l '( )N l y n o t c ohmi c o l . s/.,tll ofo f v ari eus count r ie s III d tl 1 lL\iilnt in .wn1!(J I 'Y an d ( ie Rl gn l! !l " { I Y o om /p or ed t o thoee in1 lUS CUltl Lparticularly new. At rese l o t I J !l I apOIL,constitute ideul me n S P i nt, h o w e v e r However, >I 1111'(' number of till", I if - III 0 coun t el 'n ~ ti ll 'hines self-exploded .sweeplflgoll'l empoyed' ~ "various type" f mi in c o m b i l l a t i l1' (d) The exactn ," uf the f i n i heds o llllnesthes'" . , f d' tribut A . ,b ' , ' . "eepulJ> tn eel.' 0 goo S?,-fja /-wU e to mel'Wan intlu 'i1'Y,ecomes l IuDOSt llnpOSSlbl '" , ,0 ~ ", e, .c!.'lJan t1 'I'he rneriean mmes external an-p1"'8mre 1 1 1p emm e h a d 1. . '1 0 r I ~ 1 ' , 1:i h' ,veen n o n ' c l J ; i s t ,HlaJ'l.IIICe 1 at n first glance somewhat rough butuse 0 t e magnetic an d aCoU8t ic 'P . '~nplaces w h er e e rc a ct ne s 8 is 1'equir ed the pU feo t

t oge t lUl l ' wo~~ Jtave ma de cOUJntcf l~n~i&tJ8sf 1 aanu fac t ' lJ l r e l' if J beyond the abi l i&y of Jap.ewil 'cmcly dif!wult an d (Jom." ' '- t~ ~s e i1 'C"I.~t1 'Y 'tkem.i 'b'- rW ~ ~waep '!ell!, nnp081i~ 1. 1/ Five of t J 1 ( l mechanisms of t ile A-3, .3. If a device ! Iad been !itt 'I i lCOU tic mine were examined at Kur IH enul, Inp loda tllem ' I f . t l u Y ! I fell on lama th e 1 0 e I, pire of their huving been dropp d on land none

bam, ell~~! mOl'll cl(ectivc , Among I;c I:Uld f them. s,uffer (1~n~ dll;ffia!;teand their uniformityby AmeI1Cil. acol lsldemblenwnber fell 1ll1'S f sensrnvenees ]S indi 'otn6 of the Pl'ogl'es ofreseal'Chon these led to v " onlltruitAmerican i ndustry.111 If - !LllOUS means o f,g. these had been self ex Iodin . 1 i l I , There were no mine echnicians illtZ07l, t o p ro ba ble d am .n ne aim7 p g, In tlIJapan comparable to those in America and thePrinci l ,-" mua to a bombd' l . , .P 1< $ of theZ1' 001!S t1'UO t' ' up a y o f $u. h . a ' b17. t it y by i1111.enca 'wa,.s the Oc -b e ff l r e v eaZed to the IJ1lW Mn 'Would n o t j~08i(l1I fm' surprise (J IInong t i le mine 8 'pec io]Mt s inw - r Jo basis would h tke {~l'anese Navy,pla _. ave been a v a i J a b l e~ d~~ of sweep methods and the ma t I ' ! 5, Generali t ies,1 1 S pl rl tU al e lf t "b e e n "'!'eat ee on the enemy II'Guldlu a. AltllOugl! the e ffe ot o f" tlte mineUnit d ,Reason for the failure 0 1 ' l J)a l' f~7e was ver y; g1'eat imust not be overlooked

Sllbjee t tates to , l ise such a . device al'llthut ~.t -8e ss enc e w a,.s i n & wp e1i or ifllj in a ir p ow er .C of much dlScussion. AmerlCa secured results from its airplane mineo. Mechlll1is _. wadai'e far ill excess o f any resu lts obtainable by'eT' m device. Japan's air strength, T he ? ni ne warfm'e, im sh01't, "e111,8' Z 7 'r-~orC01lsfl'l'uot' C/~a l l>1,8m device hOles 8~ WtUi me1'e y ano t h er pluNe of ai r warfare.

th,e apecla. l iat unz ~nd spealcl! well of th o ([bilil! b . "It is 0. I1 l iJT1 '}edthat "lI!ineswill bemore [ he a p lia n . , e l 1 6 manufaafju,1'cl's, Furl]; transported by airplOines ' l IW1'C and mor e in themines ho Pu ca tlO~ of the pI'inciple to I I S 1 l \IT future,~eclUJjcale:per~ s~ Il~ndrar-s ightedness o f 1 It is bel ieved that ~eve~opmell t wil lIJI Japan at the \~hich IS.far beyond that of Utt'be par ti cula rly a long the . followmg Jines,. A - a , .1\-5 Ilnd : . \ IPI esent tIme. That is to suy,II 1, They will b come more S usiti veveloPment f sh f -l l r ne eh a, ni sm s i nd ic at e t ha ~ a nd opernble-at gt'eater depths,special e J ec ta . ?Jt wave Communication opII1 2, Explosive power will be in-flc e W e 't - db - d ' ,!lin t u b e Q I ' 1 U l by uSing Ii . small type I'I~ crease eyon present eXI)!os:t vepower and speCialg ow l llbe i ind"eed 1 ',I.. explosives will be l lsed "F 'I II. C ever luC.. 'alld M 0 Ul t leI 'moJ ' ' ,' tl ~ fb - rnechanis e It IS eleal' thllt IR, B, O ve r-a ll E ffe ct o f ilfi ning C 'a mlJa ig n.y teleph IIls are un It li t' f de5lgt'f~c t " Ollil comln" . pp ca IOU 0" The following ex:crac[Sa re taken from the "lilt th . . 'lfilcatlO . d 1 ' lel'illl ey W ere ) . 11engmeers n il Interrogations of Captain KyU%~ Tamura, l JN.is!,s t 8 SPeaks WI ' I J 1~rfected with telephone~: (USSBS NOS 34, 103,285),o apply theit OJ the ability of those Spel'lj'rl knOwledge. UlAfr

~11c1 elecki, Ie COmbjnat' f ' I d s w i r .IS IIlso Cui elJt'rgy _ _ ,IOn 0 BLUe yn '41 The Japanese f ir st discovered miL1!lS in1111 l t 1 11 li s i l e . seen III the -6 lIleehanv 110meWiltet':;l in lU!2 . These '1'1'1'6 pl'tlSllnlllbly laidPIece of w O I'k . .

by submar inc, A few I1l ti p s we r e s unk and 1WI


27/70

Q. "I w ouhl lik e (0 know i f Ibj s i n t r-ns iv . . milleIlI'bl!rmll atfl'dml tht' umrule of 1 1111


28/70

real eifective countermea lU'1} being prodll~ec1 In'h I th ink t hat y ou should ut tve tr ied toquuIIn""" tdevelop- omethina to prevent th~se pon '~eouse rple ionsand sympllth ti explcs ions , I tr ied towork 011i t but couldn't find out why so many ofur minas Itrploded for 110 apparen 1:11 on, Itomething worth studying, It might haeeif he mines had been d ispe rsed more, 'Q, "What inyour opinioni the bestmethod forning by airplane 1 Is it best to drop a gresmber of mines lit interval , or to drop a fewday'"\ .. "In my op in i on con t inUI )US mining is ' fM1'8t ha n o ca a ionallal 'ge-scole m'ining. OfI u rge -s e nl e a tt ac k s a t i n te rva ls also cause

10 of trouble, " b u t wh e n YI)U cl)lIfJilLtUlll'!l(" , "oppedem it me an t that w e m ere wing equifY1Mn. t 9 4' s p e r day. They were always on the lookout.

It big load dl'Opped ut intervals , we hadrespi te for a few da.ys . A. continuous defense isrd tokeepup. From the po in t of v iew of ItUmgit i.8 fu r b et te r t o rJORtimwU8l;y feed mines to

g iven a re a O cc au 8e w e R ev er are c onfident o f achanne l . With a bi load in one place wit i s c le an wIlen swept."Q. "In your opinion, Oaptain TA1IffiRA, dothink that the UNITED T TES dividedminin tr and bcmbim- effort properly! Inw o rd s d o y ou think we should 1111" ,ene l 'e a adng eliort and possibly commenced miningrations sooner'!""The rmdt of B-w min;i;ngWM 80 ef fec tivet t I 'e 8h ipP ing tha: it er/Jent'llcll;y s tw .u ed the

lltJry. I th.ink you, probably (lfJ'U.ld have 8l.0'l'f;..th e 'IDa,. by b eg in ni ng e a rl ie -r .""Doyou think that the planes used inminingeifective'than an equal number of bomb.p la ne s l '"Y e,J I d o.""After II particular type of mine Was dis-h ow lo ng w o uld it norma.lly take to workand put into effectIicountermaasure~"

. "Tbe time required fo r each type of miDesS~o110:Vs: 'f~gnetic (needletype)-lmonth,e ti c (mdll cti on type) -2 months, acoust icfrequencY)_2 weeks, acoustic (low fre-ey)-unable to construct effective COlUlter-but resea.rch was completed in a m nthty. os,ure pe rrune-llnable to construct eifecti'?etumeasu re bu t researc.h completed in 3A very few mjnes were Swe p t with tsweepers. " . ne

Q . 'Wbn& pet"ce.n~l~eI Of" ships which st ro schooncL's \VIIS adopted bu t this, too, WIlS threa L-mine were 10 t comp e e y . dc . 1before i t could be put to prucl icaluse by, "D a to the fact that mines 1l01'D;utlly ene liVe.! . t . t11.., U 1 b. t "0 \\"~th merican bombi

Documents

USSBS Report 78, The Offensive Mine Laying Campaign Against Japan