EFENSE INSTALLATIOON IWO JIMA

Classification ch*ng*d to

ED

Maj., Inf. Custodian

CINCPAC-GINCPOABULLETIN NQ. 136-45

10 JUNE 1945

8 JUN1945

I

Defense Installations

on

I WO JIMA

flaintly

CINCPAC-CINCPOA

FLEET MARINE FORCE

V AMPHIBIOUS CORPS

3rd, 4th & 5th MARINE DIVISIONS

JICPOA L" 5 0 6 0 7 - 23 THRU 144

UNITED STATES PACIFIC FLEETAND PACIFIC OCEAN AREAS

MCH/cc HEADQUARTERS OF THE COMMANDER IN CHIEF

10 June 1945 - Serial DIS-1OO93O

From:To:

Subject:

Enclosure:

1.

Commander in Chief, U. S. Pacific Fleet and Pacific Ocean Areas.Distribution List.

CINCPAC-CINCPOA BULLETIN No. 136-45.Defense Installations on Iwo Jima.

(A) Subject bulletin.

Enclosure (A), forwarded herewith, need not be reported and when no. . _longer of value should be destroyed. No report of destruction is necessary.

M. LBpENDRE,By direction.

Copies ARMY5 ComGenAAASch Ft Bliss Tex2 CO AMS War Dept5 Chief of. Engrs War Dept5 Chief of Ord War Dept2 Chief Sig Off War Dept5 ComdtCASch Ft Monroe Va2 ComdtCom&GenStaffSch

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10 June 1945 Serial DIS-1OO93O

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Table of Contents

JAPANESE DEFENSIVE PLAN AT IWO JIMA . . . . . 2-6

ILLUSTRATIONS . . 7-119General Terrain Features 7-16

Beaches . . . . . . . . . 7-10Terrain Inland * , 11-16

Obstacles and Mines 17-20Mines 17-18Trip Wire 19Anti-Tank Ditches • 20

Caves 21-25Coast Defense - Artillery 26-39

15 cm CD Guns 26-2614 cm CD Guns 29-3112 cm CD Guns 32-3312 cm (Short) Naval Guns 34-378 cm CD Guns 38-39

Antiaircraft and Dual Purpose Batteries 39-6412 cm DP Guns 39-4210 cm DP Guns 43-457 cm AA Guns 46-48

25 mm AA MG 49-5813 mm MG 59-60Searchlights . . . . . . . . 61-64

Blockhouses 65-70Covered Artillery Emplacements 71-86

120 mm Howitzers 71-7475 mm (Type 38) Field Guns 75-7875 mm (Type 90) Field Guns • 78-8047 mm Ant i-Tank Guns 8I-8537 mm Anti-Tank Guns 86

Open Artillery Emplacements 87-8847 mm Anti-Tank Guns 8737 am Anti-Tank Guns 88

Mortars 89-95320 mm Spigot Mortars . ­ 89150 mm Mortars 90-9281 mm Mortars 93-94Grenade Launchers . 95

Rockets 96-IOO200 mm Rocket Launcher 96-98250 kg Rocket Launcher 9963 kg Rocket Launcher 100

Pillboxes 101-103Rifle Pits 104-105Tanks 106-108Dummies 109-111Radar and Radio Station 112Revetted Vehicles 113Air Raid Shelters . . . . . . . 114-115Ammunition Storage '. 116-117Miscellaneous ... . . . . 118-119

MAP APPENDIXEnemy Defense Installations as observed from ground study.Arcs of Fire for Casemated Coastal Defense Guns on Iwo Jima.Anti-Aircraft Defenses.Blockhouses with principal directions of fire indicated.Covered Artillery with principal directions of fire indicated.

Japanese Defensive Plan At Iwo JimaThe strategic importance of IWO JIMA. need hardly be emphasized. Its value as

an airbase midway between the MARIANAS and the heart of JAPAN has already beenproved. After the occupation of SAIPAN, the Japs must have known that IWO would beattacked* The only question was VHEH. The story of their haste in constructingdefenses is told in aerial photographs from 15 June 1944 until D-Day, 19 February1945.

INCREASE OF FORTIFICATIONS

At the time SAIPAN was invaded, only AA defenses, hasty fire trenches, and pre­liminary beach defenses had been prepared at IWO JIMA, By September 1944* positionshad been constructed in depth behind the beaches. Company and platoon positionswere then in evidence, and concrete pillboxes and covered artillery emplacementswere under construction. By December, most beach positions were completed and hadbeen strengthened by the construction of heavy concrete blockhouses. A cross-islanddefense line in depth protecting the northern part of the island was springing upalong the high ground north of Airfield No. 1. Additional AA defenses, increasednumbers of covered artillery and coast defense guns, and more and more concretepositions and minefields on the beaches were noted on each succeeding photographiosoftie. By D-Day, key positions had been connected with pillboxes and were protectedby covering fire from artillery, anti-tank guns, and mortars, previously sighted in.

Intelligence prior to the invasion of IWO indicated a formidable garrison forcewith many major caliber weapons and extensive tank and personnel obstacles; however,aerial photographs and maps gave only a limited picture of one of the enemy*s bestdefensive weapons, the terrain. An amphibious assault in force was limited to theeast and west beaches of the narrow southern part of the island. These conditionsgave the Japs an advantage in preparing defensive positions for all-around security.Only small groups were needed to cover very narrow beaches with steep exits alongthe northern coast.

COVER AND DISPERSAL

, Captured documents, confirmed by ground study, indicate the enemy's battlestrength was conserved by countermeasures against shelling and bombing. The terrainwas well suited for cover, and caves were so numerous in some sections of the islandthat it was impossible to plot them all on a 1:10,000 map. The coarse, loose, vol­canic ash kept damage from shell fragmentation to a minimum. Ammunition, stores,and personnel were dispersed in caves and behind protective terrain where navalgunfire and artillery could not reach them.

CAMOUFLAGE

Camouflage encountered and camouflage discipline during construction, as evalu­ated from aerial photographs, was excellent. Positions were at all times coveredwith materials which blended into the surrounding terrain and vegetation. Spoilfrom excavations was planted with grass to obliterate traces of military activity.Natural vegetation was used to a large extent to conceal well-built positions fromaerial attack. While such practices could not always elude photographic interpre­tation, nevertheless many positions were not detected until gun fire had blown awaythe concealing vegetation. Maximum use was made of IW0*s sparse growth for con­cealing trenches, rifle pits, machine gun and artillery emplacements. Positions aslarge as those housing 120 mm Howitzers were undetected under the protective coveringof trees in their natural state.

COAST DEFENSE

Coast defense artillery ranging from 4.7" (120 mm) to 6M (I55 mm) guns wasinitially effective against our ships. All CD guns were casemated in four to sixfeet of reinforced concrete. Each emplacement was so positioned in the terrain that

it was normally protected from naval gunfire. A ship taking a CD gun under directfire necessarily exposed itself to the gun at which it was firing. Many guns wereso camouflaged that their location was unknown, until they opened fire.

ANTIAIRCRAFT

Antiaircraft batteries were numerous, including 120 mm DP, 100 mm, 75 mm, and25 mm in triple, twin, and single mounts. The Japs could not satisfactorily concealthese weapons, but their continued use against aircraft and our personnel ashoretestifies to the sound construction of their emplacements.

EAST BEACH POSITION

The elaborate trench system facing the eastern beaches had been entirelyabandoned. The loose nature of the sand suggests their presence as dummies, al­though they may have been prepared originally as hasty beach defenses before adequateconcrete positions were built. Well-constructed blockhouses encasing 25 mm machinecannons to 120 mm short naval guns were the first defenses encountered on and nearthe beach. Some concrete pillboxes and sandstone revetted rifle pits gave infantryprotection to the heavier weapons. The ground at the base of Airfield No. 1 wasmore suitable for dug in positions, and most of the infantry positions protectingthe east beach were here. The positions were not so much the target for naval gun­fire, and excellent observation and good fields of fire were afforded here. Theposition of Airfield No. 1 limited the depth of these positions to approximately500 to 700 yards. Supporting fires were delivered from the flanks using the ob­servation provided by Mt. SUHIBACHI and the high ground over the East Boat Basinand around Airfield No. 2. The area between the beach and Airfield No. 1 was steepand impossible for wheeled vehicles* to traverse. Movement of infantrymen and tankswas impeded by the loose soil with the result that they offered excellent targetsto anti-tank and anti-personnel guns and tactics.

WEST BEACH POSITIONS.

The defenses of the West Beaches were probably more extensive and elaboratethan East Beach defenses.' Airfield No. 1 permitted these defenses to be 700 to 1400yards deep giving considerably longer fields of fire and permitting a more elaboratesystem of dummy positions fronting the actual main positions and designed to drawour preliminary bombardment. The terrain was much more substantial for caves andunderground shelters, and positions were better protected from our naval gunfire.

SURIBACHI POSITIONS

In the south a cross-island defense line was constructed on the terraced slopeswhich guarded the approaches to Mt. SURIBACHI. It consisted of a maze of concretepillboxes, bunkers, shelters, and blockhouses which were capable of all-around de­fense and were mutually supporting. In addition to this elaborate surface organ­ization, there was an equally elaborate subsurface organization of shelter, passage­way, living quarters, storage areas, and cave-type firing positions which providedadequate protection against the heaviest of bombs and shells. The excellent ob­servation from the heights of SURIBACHI and the high ground around Airfield No. 2were the feey to controlled artillery and mortar fire,

MAIN DEFENSE BELT

Since landings in strength were limited to the east and west beaches near thesouthern end of the island, the enemy prepared his main defense in depth in a cross-island belt. Beginning in the west at the rocky cliffs to the north of the westernbeaches, it stretched east across the island to skirt the southern end of AirfieldNo. 2, and terminated in the cliffs which form at the northern end of the easternbeaches. The center of this belt was 2600 yards deep. It gained its strength fromits depth and its concrete and steel structures, positioned so as to obtain longfields of fire which were carefully calculated and tied into the overall defensesystem. Reliance on caves as a shelter and a fighting position was increas'ed here.

Most of the positions showed excellent engineering and terrain appreciation. Com­munications were maintained by trenched wire, radios, and a labyrinth of undergroundtunnels connecting all areas. One of these tunnels was explored for 800 yards,and 14 entrances were found; it housed two battalion command posts and was equippedwith lights and telephones. Artillery, including heavy mortars and rockets in andbehind this defense belt, could cover most of the beach area. Positions were pro­vided with complete preregistration data.

Strong points were established around commanding ground, Conorete-faced cavesand infantry positions in the erosion-made crevices were frequently so close to­gether that an equally strong defensive position existed only a few yards to therear or flank. Contact became so close that safety of our own troops prevented useof artillery, naval gunfire, or air support in reducing these positions. One bluff,forming something similar to an amphitheatre, contained two terraces and three tiersof concrete pillboxes and oaves*

FINAL DEFENSIVE AREA ' • •

North of this cross-island defensive sector, the extremely rough terrain fromthe coast to 2000 yards inland created a natural defensive area. The number ofcaves and terrain characteristics somewhat compensated for the reduced amounts ofconcrete and steel. These features, coupled with the masses of men employed, tendedto make this final defensive area equally as strong as the main defensive positions.In attacking these positions no Japs were to be seen, all being in caves or crevicesin the rocks and so dispersed as to give an all-around interlocking defense to eachsmall compartment. Attacking troops frequently were subjected to fire from flanksand rear more than from their front. It was always very difficult and frequentlyimpossible to locate exactly where defensive fires originated.

In defending IW0 JIMA, the Japs employed one basic tactic which in a sense wasa departure from the Japanese defensive operations hitherto generally encountered.This tactic was simply to occupy previously determined D-Day positions and maintainthem, without recourse either to costly rtmain effort" counterattacks or organizedwithdrawals. This plan was not only simple in conception but in general was skill­fully executed and well adapted to the terrain of IW0 JIMA. There were no organizedattempts made to counterattack our beachhead, no large scale night counterattacks,no "all-out" banzai charge. Instead, the enemy committed a minimum number of troopsto the southern beach area and defended it by delivering heavy volumes of fire fromboth SUHIBACHI and the north so that even when the southern area was finally taken,the bulk of the enemy's forces remained intact and were well entrenched in the mostheavily fortified part of the island. The enemy, by continuing to follow his simplebut basic defensive tactic of occupying a position and refusing to yield until dugout and killed without counterattacking and without withdrawing, was able to main­tain organized resistance for over twenty days. There were no tactical withdrawals,no retrograde or delaying actions in the military sense, though in some instancesisolated withdrawals were made to preserve units and individuals threatened withinevitable destruction. It is now known that this defense of holding to the endwithout counterattack or withdrawal was the express plan conceived by the CommandingGeneral. It was this simple tactic, coupled with the incredible rocky terrain andthe maximum use the enemy had made of this terrain in constructing fortified posi­tions which made the capture of IW0 JIMA so difficult*

ANTI-TANK TACTICS

Captured battle plans indicate the enemy's fear of our tanks. Mine fields,magnetic mines, and explosives carried by hand were employed at the beach where theloose sand seriously impeded the movement of even full-tracked vehicles. Anti-tankguns, mainly the high velocity 75 mm and 47 mm, were the principal weapons employedinland. Many anti-tank guns had one or more supplementary or alternate positions*These weapons were sited in terrain affording fields of fire covering possible tankroutes from the beach; however, considerable emphasis appears to have been placed onlocating an emplacement where it was protected by an abutting bluff or terrace, whichshielded it from frontal flat trajectory fire.

BLOCKHOUSES AND PILLBOXES

Blockhouses and pillboxes near the beaches on the more open terrain were almostinvariably sited for flanking fire. Wherever possible, a pillbox was behind a naturalmound of sand. It often had only a small fire port which allowed approximately 30°of traverse; however, there was a sufficient number of mutually supporting pillboxesto offset the restricted field of fire of each weapon.

Many blockhouses near the beach had sand piled as high as 50 feet in front ofthem. A narrow fire lane through the sand revealed the direction of fire, but manypositions were so well protected that they were still firing until reduced by in­fantry. Pillboxes were protected similarly; infantry commanders often found itnecessary to request main battery fire from naval vessels when secondary batteryfire could not blast the sand from in front of well built positions.

OF TANKS

Relatively few tanks, medium and light, were present on IWO JIMA. The roughterrain, size of the island, and fixed nature of defenses probably account for thelimited number. Their manner of employment was as an anti-tank weapon. They wereused in support of the main cross-island defense belt either in a revetment or be­hind protective terrain, camouflaged and stationary. Their 37 mm, 47 mm, and 57 mmguns fired anti-tank and personnel missions like the many 47 mm guns. Reports in­dicate small tank units were to be employed to support local counterattacks. Thereis little evidence they were so used. The torn up condition of roads and constantartillery fire may well have prevented any movement.

ARTILLERY

Artillery tactics were characterized by good observation and careful preplanningof fires. Range stakes were found in the vicinity of landing beaches. The elaboratecasemated structures in which artillery pieces were housed, the cave positions fromwhich mortars and rockets were fired, operated to limit the number of pieces whichcould be brought to bear on a single area. Despite perfect observation, artillery,rocket, and mortar fires were never massed against us in the same manner in whichwe mass artillery fires. Dual purpose guns were used to fire time fire over ourtroops*

An artillery group gave coordination to all field artillery and mortar employ­ment; coast defense and AA artillery were not included in this command. Mortarshad the primary mission of filling in the gaps between the fires of the other guns,but after the land fighting stage was reached they shifted to control of sectorinfantry commanders.

The principal locations of mobile artillery were in the higher ground north ofAirfield No. 2 with forward OPs in prominent elevations along the main defensivebelt. There definitely were more weapons at the disposal of commanders than wereorganically assigned to the units. The fixed nature of the defenses permittedpersonnel normally used for ammunition carriers and for the movement of mobileweapons to be employed to man additional weapons added to basic tables of organ­ization.

MORTARS AND ROCKETS

Although approximately twelve 320 mm spigot mortars were encountered on theisland, their effectiveness is doubtful. Emplacements were well constructed andconcealed but only a few rounds were fired. IWO's terrain was suited for the useof the many 150 mm, 81 mm and smaller mortars found there. Ammunition was storedthroughout the northern half of the island in caves and hasty firing positionswere utilized at the entrances. The 150 mm mortars were used to fire on landingbeaches. These weapons and the smaller mortars were withdrawn as the situationdemanded.

Three types of rockets were used as artillery weapons. Several positions weresighted for firing at ships approaching close to shore. The V-trough launcher wasused for 63 kg and 250 kg aerial bombs with rocket motors providing the propellingforce. A 200 mm rocket was used from a mobile-type launcher and a launcher which ismounted on a mortar-type bipod. Rockets were dispersed in deep draws over the north­ern portion of the island and the launchers could be moved to the site of the am­munition.

* * * * * * * * *

It is evident that little was left undone by the Japs in constructing as for­midable ground defenses as possible on an island with the size and particular terrainof IWO JIMA. A study of Japanese defense installations encountered in the field ispresented with photographs and drawings on the following pages.

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B C D E A B C MAP APPENDIX

CINCPAC-CINCPOA BULLETIN NO. 136-45

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IWO JIMA ENEMY DEFENSE INSTALLATIONS

AS OBSERVED FROM GROUND STUDY

19 FEBRUARY —19 MARCH 1945

THE SPECIAL GRID SYSTEM IS SUPERIMPOSED ON THIS MAP IN PURPLE COLOR. THIS SYSTEM IS TO BE USED FOR PIN POINT DESIGNATIONS.

THE ARBITRARY TARGET SQUARE SYSTEM IS SUPERIMPOSED ON THIS MAP IN SALMON WITH BLUE LETTERS AND NUMBERS. THIS SYSTEM IS TO BE USED FOR AREA DESIGNATIONS.

THE NUMBERING OF THE IOOO-YARD TARGET AREAS AND LETTERING OF THE EOO-YARD TARGET SQUARES HAS NO RELATION TO THE NUMBERING USED IN THE GRID SYSTEM.

V W X PIN-POINT DESIGNATION OF RJ106 IS BC 750-709 RJI0 6 IS IN TARGET SQUARE 132 A

CASEMATE OR BLOCKHOUSE COAST DEFENSE EMPLACEMENT, UNOCCUPIED A A HEAVY FIRE CONTROL CENTER A A AUTOMATIC FIRE CONTROL VISUAL MACHINE GUN (6.5-7.7 mm) OBSERVATION POST A A TWIN MOUNT OBSERVATION TOWER A A TRIPLE MOUNT PILLBOX A A DUAL PURPOSE PERSONNEL SHELTERS-BELOW GROUND FIELD ARTILLERY-HEAVY DIRECTION FINDER FIELD ARTILLERY- LIGHT SEARCHLIGHT COVERED ARTILLERY SIGNAL TOWER ANTI TANK -MEDIUM AMMUNITION ANTI TANK -LIGHT COMMAND POST MORTAR BURIED BUILDING ROCKET PROJECTOR, SINGLE AIRCRAFT REVETMENT VEHICLE, ARMORED

THOUSANDS OF CAVES USED FOR DEFENSIVE POSITIONS, PERSONNEL , AND STORAGE HAVE

R S­ T NOT BEEN PLOTTED.

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CINCPAC-CINCPOA BULLETIN NO 136-45 LJ

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THE SPECIAL GRID SYSTEM IS SUPERIMPOSED ON THIS MAP IN PURPLE COLOR. THIS SYSTEM IS TO BE USED FOR PIN POINT DESIGNATIONS.

THE ARBITRARY TARGET SQUARE SYSTEM IS SUPERIMPOSED ON THIS MAP IN SALMON WITH BLUE LETTERS AND NUMBERS. THIS SYSTEM IS TO BE USED FOR AREA DESIGNATIONS.

THE NUMBERING OF THE 1000-YARD TARGET AREAS AND LETTERING OF THE EOO-YARO TARGET SQUARES HAS NO RELATION TO THE NUMBERING USED IN THE GRID SYSTEM.

PIN-POINT DESIGNATION OF RJI06 IS BC 7 5 0 - 7 0 9

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THE SPECIAL GRID SYSTEM IS SUPERIMPOSED ON THIS MAP IN PURPLE COLOR. THIS SYSTEM IS TO BE USED FOR PIN POINT DESIGNATIONS.

THE ARBITRARY TARGET SQUARE SYSTEM IS SUPERIMPOSED ON THIS MAP IN SALMON WITH BLUE LETTERS AND NUMBERS. THIS SYSTEM IS TO BE

THE NUMBERING OF THE IOOO-YARD TARGET AREAS AND LETTERING OF THE 200-YARO TARGET SQUARES HAS NO RELATION TO THE NUMBERING USED IN THE GRID SYSTEM.

PIN-POINT DESIGNATION OF RJIO6 IS BC 7 5 0 - 7 0 9 RJ I0 6 IS IN TARGET SQUARE 132 A

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THE SPECIAL GRID SYSTEM IS SUPERIMPOSED ON THIS MAP IN PURPLE COLOR. THIS SYSTEM IS TO BE USED FOR PIN POINT DESIGNATIONS.

THE ARBITRARY TARGET SQUARE SYSTEM IS SUPERIMPOSED ON THIS MAP IN SALMON WITH BLUE LETTERS AND NUMBERS THIS SYSTEM IS TO BE USED FOR AREA DESIGNATIONS.

THE NUMBERING OF THE IOOO-YARD TARGET AREAS AND LETTERING OF THE 200-YARD TARGET SQUARES HAS NO RELATION TO THE NUMBERING USED IN THE GRID SYSTEM.

U ! V W ;X PIN-POINT DESIGNATION OF RJIO6 IS BC 7 5 0 - 7 0 9

RJ I0 6 IS IN TARGET SQUARE I32A

B C D A B C D

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CINCPAC-CINCPOA BULLETIN NO 136-45

ARCS OF FIRE FOR CASEMATED COASTAL DEFENSE GUNS

ON

IWO JIMA PLOTTED FROM GROUND STUDY AND CAPTURED MAP

49'

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46 '

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45 ' 45'­

17' 18' 19' 141 20" 21'

JICPOA L-50608-5 5

Cleared of mines, . t theshoulders andof road is still mined Extent of field not > nown flints are. 3•"•*"'tf6 ' s//Us iv/ vc/sficM r) 6 mines removed

252 253 Single nbrn nemispnencaiarid bombs reported in Underermine mines Box,area. 3-/0-45 stick mines <f others

This area (qpproK 100 yds square w of rood) onrained 6 Herr, mortar grenodand 53 icol mines. (-5!Magnetic mints armed 27-45 See In&drt £ (H Cosi of flares. d caps / ammo

(3) Toot-measure

.̂ r ry of mined area

baHelit p. fuzes (4! BOA /nines remove c i3>Shape charge(I) STjck qrenadetz) s' Duds,

1 nest Tieiqsconrained a i (i) &UA mines and (21) Taoe- Measure // were removedape-neat vre See Insert '/f- B~- C HIRAIWA BUY uop bomb disper \al area (65 to 70)

area (-9B) bombs 250 Kg dispersei 1 in groups of S. id £0 on each side groups IS ft. opa

easur&4 ydstich. mines (I) ROW 2 /7( rn mines250 kg bombs iv ydstick !3) Rows / Hi rn /nrnes

mines «? rows removed. /orf. her we en rows 411 removed.

This field consisted of 4 ro parallel to the beach for i

The mines were 63 kg < 'ardsrick mines were lashi ur/ed near the surface .

an overage of 35' Qgarfmines in the field. This

See Insert 0'

s or mines running approxudistance of over 1000 yar

nd 250 kg bombs with no 1 d length-wise TO the bombs The aerial; bombs were place There were approximately area i j^7rd^m9a'5

I- imr

was also Clean go of t 6­minat,

Z horn road bl

min&s)

ed ynK

Insert F Pattern of Anti- Tank Trench

ines 6 J (i7j Conical <fAnti-mines Scotterec

This oreo conrained 57 Co/,and 19 Hemispherical mines

field located approt red pattern not

Removedjs) loolb Sombs

>e measure mines mines

e)Tonh mines Magnetic2) $o kg bomb a

charoe arena cm 2"Terrace wen si

I raws ... to the beach on Terrace. The rows

ZSaparT, Double and si horned mines were fovn

Removed (2*) Ant, nvasioni Horned) mine

cM mines,sonnet,

a.

Horn rninee, ydstmines \yAnfi-p

Tape measure

Some irunm Mfrnp-Hind son contdbieci scrfetf-pi

Tbe\ Conicalmin?S-w 3 rowi(f'f&rrace) onk £ ro (2 terracer),' stoy$t*4di it rt beach and 25'apart ' Hoi were present for additionc mines OneDepth chargefound- (See insert f'J.3/

63'j kgbombs, \yydstic Removed (eto box mine.5

This area contained in series of 2 with connecfing. a//

/tasty mine fie 4 yds tic A f 3 removed. 3 3

JLXtll),oito mines

horn mines i row ac'ft, a/so rape-measure,

off

nsert G" 60) Kg be •nbs remoireo' 3-i-fS rows Tort ap Pattern of mines This area contain

do/ mines I claare C) Incendi ary re. voved. 3-3-45 20 ft apart.

charge p/aced /Yard shek mines road with 2 yd ttap naz ard pattern

either side of Tape -measvre mines

This area has be&n le rot* of horn found dps turned upside, down

25 stick mines base as Depth Charge used. 16 MARCH 45

D plus 25 Mine field c/eared z no data on pattern or

Removaa mines on Red deo h If 2 On MINE SITUATION MAP (19)Smqle horn mines Green Sfemovcd

Ci)2 horn oeoch mine of ((» US A'oyy gun firs (6OJ US mcrfor duds Mined area has bee neutra/jze d of IS) VS. Novy rocket- </</, f/'/ct/on qrenodes, <2) USAircraft duds Scoftcrev md/scrim natelyt a// are IWO JIMA also srr?o//er duc/s stored am me

Compiled by Corps Engineer Section from information

received from 3d ,4 th ,5 th Marine Divisions, Appro* line f fi­(i every / / " on beech 2d Sep. Engr. Bn. and 2d Bomb Disposal Co.

(4) AP mines ItS . (/'/) fr mines '3) Jnp flora 11 HI Florns L 1 wmmmm•1

0 500 1000 2000 yds

CINCPAC-CINCPOA BULLETIN NO. 136-45 MAP APPENDIX

JICPOA L- 50608-56

GENERAL TERRAIN FEATURES -Beoches

Amphibious tractor stuck Inloose sand on East Beach.

Deep footprints indicateloose character of sandon beaches.

Beaches

Marston matting on EastBeach essential tovehicular movement overthe soft sand.

Bogged down Jeep withchains on East Beachsubsequently damagedby enemy fire.

8

Beaches

Wave-cut terrace on EastBeach.

Terrace on East Beach andamphibious tractor.

Beaches

Steep gradient of beach com­bined with looseness of sandmade movement difficult for"vehicles and troops.

View of terrace Just inlandfrom Blue Beach #2.

10

Terrain Inland

Looking west. This Is atypical area inland alongthe West Beach. (TA-163J)

Clumps of vegetation inthe central areas con­cealed trenches, riflepits and MG positions.

Terrain Inland

Covered artillery posi­tion housing 47 mm ATgun firing down runwayof #2 airfield. Typeof terrain in which gunemplacements were leastvulnerable to naval gunfire. (TA-183C)

Areas of this sort pro­vided excellent cover tothe enemy in his attemptsto infiltrate our lines.

(TA-E33M)

12

Terrain Inland

Approaching Hill 362 show­ing the natural ruggedterrain which confrontedtroops. Since troopscould advance here onlywith great difficulty,this terrain was a decidedasset to the enemy.

(TA-216N)

Looking, west from thi:area showing sparsevegetation. (TA-216A)

13

Terrain Inland

m

Looking south showing therugged terrain approach­ing Mt. Suribachi.

(TA-132R)

This picture is typicalof cave-infested north­ern area terrain.

(TA-234D)

14

Terrain Inland

Rocky outcrops and scrubvegetation characteristicof the northern one-thirdof the island making move­ment of troops difficult.

Rocky terrain near northcoast provided the enemywith natural positionsfor MGs and riflemen.

15

Terrain Inland

- *

View of terrain typicalof that encountered Invicinity of Hill 382.

(TA-200Y)

Trench cut through reckleading to gun positionsnear East Boat Basin.

(TA-166D)

16

OBSTACLES AND M I N E S - Mines

Close-up of taried oildrum with the top cutopen and ready for land-mine to be emplaced.Due to the enemy's dis­rupted schedule causedby cur bombing prior toD day, they did not havetime to set up the minefield in conjunctionwith the oil drums.

(TA-180X)

View of West Beach showing55-gallon oil drums whichwere to be used as landmines. Electrically con­trolled mines were to beput into the drums to hin­der our landing on thisbeach

17

Mines

250 kg bomb burled insand as land mine.These mines were fuzedwith yardstick minesPlaced on top of thebomb and secured inPlace with fine wire.Many such mines thusemployed were locatedstrategically, andwell covered with firefrom AT weapons.

(TA-165 0)

View of the West Beachshowing one-horned coni­cal land mines. Theentire West Beach wasmined.

18

Trip Wire

Trip Wire. (TA-201S)

This was the only evidenceof trip wire or barbed wirebeing used in this area.It proved ineffective Instopping troops from land­ing or advancing.(TA-148H)(looking east)

Anti-Tank Ditches

View of AT trench,(TA-198H)

View of AT trench,(TA-198H)

20

CAVES

Interior view of cave.This cave had a seriesof caves leading offin different directionsand connecting withother caves In the nearvicinity. Food, ammu­nition and .clothingwere found In thesecaves indicating troopshad been quarteredthere. (TA-199U)

Interior view showingsteps leading out of thecave which is about fortyfeet under ground withlarge rooms throughoutfor the quartering oftroops. (TA-199U)

21

Caves

Typical entrance to ex­tensive cave network,extending from under­neath the quarry nearthe East Boat Basinwith tunnels leading asfar bs 800 yds. toMinami Village.

(TA-183W)

Entrance to cave(TA-198X)

22

Caves

Interior view of exten­sive cave•network underCD gun over East BoatBasin. (TA-183X)

Entrance to cave.(TA-216D)

23

Coves

One of many caves In for­ward slopes of hillsguarding airfield No. 2.MGs and small arms firewas received from thesepositions which providedexcellent observation ofthe entire East Beacharea. (TA-183H)

Interior view of caveshowing steps leadingdown and passagewayleading off to eitherside where troopswere quartered.

(TA-198X)

»

Caves

Interior view of entrance leading down Into cave. (TA-199UJ

Interior view of passageway In cave. (TA-132C) Entrance to two-story cave. (TA-199U)

25

COAST DEFENSE - ARTILLERY- 15 cm CD GUNS

155 mm (15 cm) CD gun show-Ing destruction caused bynaval gun fire. Reinforcedconcrete 4 ft. thick. En­trance to these casematesIs In the rear connected by-cave networks which wereused as personnel shelters,food storage and ammunitionstorage. These guns wereset about 15 yds. apart andhad a field of fire cover-Ing the entire West beachesand areas out to sea.

(TA-216D)

Ruins of 155 mm (15 cm)CD gun. (TA-216D)

26

15 cm CD GUNS

Rangefinder placed betweentwo CD guns in same areaused as part of fire con­trol equipment.

(TA-216D)

Front view of blockhousehousing a 155 mm (15 cm)CD gun. Destructioncaused by naval gun fire,Entrance Is in rear ofblockhouse with adjoin­ing caves throughout forpersonnel shelter, foodstorage and ammunitionstorage. (TA-216D)

27

15 cm CD GUNS

Rear view of 155 mm (15cm) CD gun In blockhouseshowing destructioncaused by naval gun fire .

(TA-216D)(SW)

Ruins of casemate contain­ing 155 mm (15 cm) CD gun,Two such Installations,built of reinforced con­crete with walls over 4ft. thick and connectedwith rangefinder and OP,were located on the edgeOf a cliff at TA-219A.

28

14 cm CD GUNS

View of cave entranceleading from casemated140 mm (14 cm) CD gunback. Into the base ofthe crater.

(TA-132L)

Breech-block view of oneof the 140 mm (14 cm)guns at the foot of Suri­bachl showing destruc­tion. It is known that"these guns were silencedprior to our landing butruins of these installa­tions provided cover forthe enemy and affordedan opportunity to inflictcasualties on troops ad­vancing toward Mt. Suri­bachl. (TA-132K)

29

14 cm CD GUNS

Front view of one of the140 mm (14 cm) CD gunsshowing destructioncaused by naval gun fire

(TA-132K)

Front view of one of the140 mm (14 cm) CD gunscasemated at the foot ofMt. Suribachi. They wereconstructed of reinforcedconcrete about 4 ft.thick with tunnels lead­ing from the rear intothe base of the mountainand connecting each in­stallation. These tun­nels also connected topersonnel shelters, foodstorage and ammunitionstorage. (TA-132K & L)

30

14 cm CD GUNS

STAIRS TO AA GUN ON ROOF

ENTRANCE TO ADJOINING ROOM

Plan view of 140 mm (14 cm) CD gun with 30-footfire port. This Is one of the four emplacementsfound at the base of Mt. Surlbachi. (TA-132 K)

31