EFENSE INSTALLATIO ON IWO JIMA I

Classification ch*ng*d to ED

Maj., Inf. Custodian CINCPAC-GINCPOA BULLETIN NQ. 136-45 10 JUNE 1945

8 JUN1945 Defense Installations on I WO JIMA

flaintly

CINCPAC-CINCPOA FLEET MARINE FORCE V AMPHIBIOUS CORPS

3rd, 4th & 5th MARINE DIVISIONS

JICPOA L" 50607- 23 THRU 144 UNITED STATES PACIFIC FLEET AND PACIFIC OCEAN AREAS MCH/cc HEADQUARTERS OF THE COMMANDER IN CHIEF

10 June 1945 - Serial DIS-1OO93O From: Commander in Chief, U. S. Pacific Fleet and Pacific Ocean Areas. To: Distribution List. Subject: CINCPAC-CINCPOA BULLETIN No. 136-45. Defense Installations on Iwo Jima. Enclosure: (A) Subject bulletin. 1. Enclosure (A)., forwarded herewith,. need not be reporte_ d and when no longer of value should be destroyed. No report of destruction is necessary.

M. LBpENDRE, By direction. Copies ARMY 5 ComGenAAASch Ft Bliss Tex 5 SIORAAFComAldAFSWPA APO 923 2 CO AMS War Dept 1 DistCom APO 960 5 Chief of. Engrs War Dept 1 DistCom APO 961 5 Chief of Ord War Dept 1 DistCom APO 962 2 Chief Sig Off War Dept 2 The-EngrUSAFPOA APO 958 5 ComdtCASch Ft Monroe Va 25 ComGen APO 7 2 ComdtCom&GenStaffSch 25 ComGen APO 27 Ft Leavenworth Kan 25 ComGen APO 77 12 ComGenAAF War Dept 25 ComGen APO 81 2 DirJointTargetGroup AAF 25 ComGen APO 96 Pentagon Bldg Wash DC 25 ComGen APO 98 12 ComGenAGF War Dept 15 CO 4thAimdGrp APO 957 2 ComGen2ndAF Colorado Springs Colo 10 ComGenTEN APO 357 2 ComGen4thAF SF Calif 10 ComGenTAFTEN APO 357 2 ComGenWesDefCom Presidio SF Calif 5 ComGenWPBC APO 244 2 CO AeroChartServAAF War Dept 3 ComGenAGF APO 86 . 2 CO OrdBDCAberdeenProvingGround 3 ComGenAGF APO 244 Aberdeen Md 3 ComGenAGF APO 245 2 ComGenAAFSATAAFTAC Orlando Fla 3 ComGenAGF APO 246 14 MISReadingPanel War Dept 3 ComGenAGF APO 247 2 OPD War Dept 3 ComGenAGF APO 331 1 ChiefPACMIRS Camp Ritchie Md 3 ComGenAGF APO 457 1 CO AimyUnitWestCoast PO Box 651 3 ComGenAGF APO 458 Tracy Calif 5 ComGenCPBC APO 956 3 ComGenSEAC APO 432 NY 10 ComGenCombatTrCom APO 957 3 BGS(I)MainHqALFSEA APO 432 NY 10 ComGenlCorps APO 301 1 CO CPICAirComSEA New. Delhi India 10 ComGenlXCorps APO 309 2 ComEasternAirComSEA APO 671 NY 10 ComGenXCorps APO 310 2 DMIGHQ New Delhi India 10 ComGenXlCorps APO 471 2 ComGenUSAF APO 885 NY 10 ComGenXIVCorps APO 453 1 ComAirComSEA New Delhi India 10 ComGenXXIVCorps APO 235 1 SuptSEATIC APO 885 NY 10 ComGenXXIVCorpsArty APO 235 14 ComGenUSAFCTO APO 879 NY 5 ComGen2273HAAAC APO 958 2 ComGenl4thAF APO 627 NY 5 C02274HSAC APO 956 2 OinCSINTIC APO 879 NY 5 ComGenSPBC APO 502 2 ComGenllthAF APO 980 Seattle Wash 1 CO 45thCABn APO 264 4 ComGenAdvCPAlaskan Dept APO 980 2 ea ArmyIsCom Seattle Wash 5 CinCAFPac APO 500 2 ComGenNZAHq Wellington NZ 5 CoordinatorATIS APO 500 15 ComGenPOA APO 958 5 OinCCOICGHQSWPA APO 500 2 CO 30thEngrBaseTopoBn APO 957 5 ComAldAF APO 923 2 CO 64thEngrBaseTopoBn APO 246 2 CO AldGeogSecSWPA APO 923 200 ComGenAAFPOA APO 953 10 ComGenFEAF APO 925 20 COEGHQSWPA APO 500 2 ComGenl4thAAComRearEch APO 322 10 ComGenUSAFFE APO 501 2 ComGenl4thAAComFwdEch APO 500 10 ComGenUSASOS APO 707 10 ComAdvAldLandHq APO 925 2 DirNEFIS APO 500 2 CO FwdEchCenBuGHtlSWPA APO 500 2 DirADVANEFIS APO 926 25 ComGenSlX APO 442 50 CinCGHQSWPA APO 500 25 ComGenElGHT APO 343 12 ComGenASF War Dept 10 June 1945 Serial DIS-1OO93O

OinCPICNYd Wash 2 AcornU'raDet Pt Hueneme Calif CO NavResLab Belief 2 BuAer/ OinCTAIC NAS Anacostia DC 2 BuOrd ComAirPac 3 CNAOpTra Jacksonville Fla 2 ComNorPac 2 AC/AS (I) AirMinA13USA 2 ComSoPac Whitehall Via CNO 2 MEIU#1 FPO SF 5 AirMinistry London Via CNO 2 MEIU#4 FPO SF 2 DMI MI 2 Whitehall Via CNO 1 ComBatRonTWO 2 ail MI 15 London Via CNO 1 ComBatDivTWO 2 DNIAdmty Whitehall Via CNO 2 ea ComBatDiv 25 CNO 1 ea CO BB 1 USNLOOSS Via CNO 2 ComCruDesPao 2 ComdtANSCol Wash DC 1 ea ComCruDiv 2 Comll 1 ea CO CA CB CL 2 Coml2 1 ea ComTaskFlot 2 Coml3 1 ea ComDesRon 2 Coml7 1 ea ComDesDiv 2 ComUSNB PtHueneme Calif 1 ea ComCortDiv 2 ComdtNavV/arCol Newport RI 1 ea CO DD 65 ComAiriant 1 ea CO DE PF 2 ComPhibTraPacFPO San Diego Calif 3 Com3rdFleet 1 ComFair Seattle 5 Wash, 3 Com5thFleet 3 CominCh 3 Com7thFleet 2 ComOpTraPac San Diego Calif 1 Coml4 1 ComServLant. 1 DIO 14ND 1 ComSubLant 45 CO SEFIC 2 CO NavalUnitWestCoast 5 OinCAlCCinCPOAAdvHq 3 CO NACIS NAS quonset Pt RI 1 OinCAlCNorPac 2 ComUSNavGrp Navy 169 NT 100 OinCJDU Navy 943 5 ComPhibsPac 100 OinCJDU Navy 3011 150 AdComPhibsPac 1 AtCom Navy 3233 2 OinCRearEchComPhibsPac 1 ea NavylsCom o/o AdComPhibsPao 1 ea CO NavAdvBase 10 Com3rdPhibFor c/o AdComPhibsPac 1 ea ComNavBase 10 Com5thPhibFor 1 CO NAS Seattle Wash 10 Com7thPhibFor 1 ComdtNOB Navy 3256 5 ea ComPhibGrp 1 ea ComNOB 2 ComSubPac ' 4 AdCominPac 2 ComSubPacSubordCom 2 ea ComMTBRonPac 3 DNINavy Dept Melbourne Australia 2 ComMTBRonsSWPA 3 SNORNethNavyinAustralia 441 St Kilda 2 ea ComSeaFronPac Rd Melbourne Australia 2 ComServPac 2 ComMarianas 1 ea ComServRonPac 2 ComNavy 3233 2 DirAdBaseComServPac 2 ComNavForces Navy 3256 5 CO InterpRonONE Navy 3256 2 ComSubArea Navy 3254 5 CO InterpRonTWO FPO SF 2 RepComDesPacCentPacFwd MARINE CORPS

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3 COIS BPF 2 Captain EscortForcee 3 COIS EIS 1 ea SenOffMinFlot 1 RAdmCom4thCruRon 1 ea CO BB 1 RAdmComDDs 1 ea CO CL 1 RAdmComFltTrain 1 ea CO DD 1 ea ComDesFlot 1 ea CO DE 1 ea CO FltTrainShip Table of Contents

JAPANESE DEFENSIVE PLAN AT IWO JIMA . . . . . 2-6 ILLUSTRATIONS . . 7-119 General Terrain Features 7-16 Beaches ...... 7-10 Terrain Inland * , 11-16 Obstacles and Mines 17-20 Mines 17-18 Trip Wire 19 Anti-Tank Ditches • 20 Caves 21-25 Coast Defense - Artillery 26-39 15 cm CD Guns 26-26 14 cm CD Guns 29-31 12 cm CD Guns 32-33 12 cm (Short) Naval Guns 34-37 8 cm CD Guns 38-39 Antiaircraft and Dual Purpose Batteries 39-64 12 cm DP Guns 39-42 10 cm DP Guns 43-45 7 cm AA Guns 46-48 25 mm AA MG 49-58 13 mm MG 59-60 Searchlights ...... 61-64 Blockhouses 65-70 Covered Artillery Emplacements 71-86 120 mm Howitzers 71-74 75 mm (Type 38) Field Guns 75-78 75 mm (Type 90) Field Guns • 78-80 47 mm Ant i-Tank Guns 8I-85 37 mm Anti-Tank Guns 86 Open Artillery Emplacements 87-88 47 mm Anti-Tank Guns 87 37 am Anti-Tank Guns 88 Mortars 89-95 320 mm Spigot Mortars . ­ 89 150 mm Mortars 90-92 81 mm Mortars 93-94 Grenade Launchers . 95 Rockets 96-IOO 200 mm Rocket Launcher 96-98 250 kg Rocket Launcher 99 63 kg Rocket Launcher 100 Pillboxes 101-103 Rifle Pits 104-105 Tanks 106-108 Dummies 109-111 Radar and Radio Station 112 Revetted Vehicles 113 Air Raid Shelters ...... 114-115 Ammunition Storage '. 116-117 Miscellaneous ...... 118-119 MAP APPENDIX Enemy 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 Jima The 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 been proved. After the occupation of SAIPAN, the Japs must have known that IWO would be attacked* The only question was VHEH. The story of their haste in constructing defenses is told in aerial photographs from 15 June 1944 until D-Day, 19 February 1945. INCREASE OF FORTIFICATIONS At the time SAIPAN was invaded, only AA defenses, hasty fire trenches, and pre­ liminary beach defenses had been prepared at IWO JIMA, By September 1944* positions had been constructed in depth behind the beaches. Company and platoon positions were then in evidence, and concrete pillboxes and covered artillery emplacements were under construction. By December, most beach positions were completed and had been strengthened by the construction of heavy concrete blockhouses. A cross-island defense line in depth protecting the northern part of the island was springing up along the high ground north of Airfield No. 1. Additional AA defenses, increased numbers of covered artillery and coast defense guns, and more and more concrete positions and minefields on the beaches were noted on each succeeding photographio softie. By D-Day, key positions had been connected with pillboxes and were protected by covering fire from artillery, anti-tank guns, and mortars, previously sighted in. Intelligence prior to the invasion of IWO indicated a formidable garrison force with 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 best defensive weapons, the terrain. An amphibious assault in force was limited to the east and west beaches of the narrow southern part of the island. These conditions gave 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 along the northern coast. COVER AND DISPERSAL , Captured documents, confirmed by ground study, indicate the enemy's battle strength was conserved by countermeasures against shelling and bombing. The terrain was well suited for cover, and caves were so numerous in some sections of the island that it was impossible to plot them all on a 1:10,000 map. The coarse, loose, vol­ canic ash kept damage from shell fragmentation to a minimum. Ammunition, stores, and personnel were dispersed in caves and behind protective terrain where naval gunfire and artillery could not reach them. CAMOUFLAGE Camouflage encountered and camouflage discipline during construction, as evalu­ ated from aerial photographs, was excellent. Positions were at all times covered with materials which blended into the surrounding terrain and vegetation. Spoil from excavations was planted with grass to obliterate traces of military activity. Natural vegetation was used to a large extent to conceal well-built positions from aerial attack. While such practices could not always elude photographic interpre­ tation, nevertheless many positions were not detected until gun fire had blown away the concealing vegetation. Maximum use was made of IW0*s sparse growth for con­ cealing trenches, rifle pits, machine gun and artillery emplacements. Positions as large as those housing 120 mm Howitzers were undetected under the protective covering of trees in their natural state. COAST DEFENSE Coast defense artillery ranging from 4.7" (120 mm) to 6M (I55 mm) guns was initially effective against our ships. All CD guns were casemated in four to six feet 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 direct fire necessarily exposed itself to the gun at which it was firing. Many guns were so camouflaged that their location was unknown, until they opened fire. ANTIAIRCRAFT Antiaircraft batteries were numerous, including 120 mm DP, 100 mm, 75 mm, and 25 mm in triple, twin, and single mounts. The Japs could not satisfactorily conceal these weapons, but their continued use against aircraft and our personnel ashore testifies to the sound construction of their emplacements. EAST BEACH POSITION The elaborate trench system facing the eastern beaches had been entirely abandoned. The loose nature of the sand suggests their presence as dummies, al­ though they may have been prepared originally as hasty beach defenses before adequate concrete positions were built. Well-constructed blockhouses encasing 25 mm machine cannons to 120 mm short naval guns were the first defenses encountered on and near the beach. Some concrete pillboxes and sandstone revetted rifle pits gave infantry protection to the heavier weapons. The ground at the base of Airfield No. 1 was more suitable for dug in positions, and most of the infantry positions protecting the east beach were here. The positions were not so much the target for naval gun­ fire, and excellent observation and good fields of fire were afforded here. The position of Airfield No. 1 limited the depth of these positions to approximately 500 to 700 yards. Supporting fires were delivered from the flanks using the ob­ servation provided by Mt. SUHIBACHI and the high ground over the East Boat Basin and around Airfield No. 2. The area between the beach and Airfield No. 1 was steep and impossible for wheeled vehicles* to traverse. Movement of infantrymen and tanks was impeded by the loose soil with the result that they offered excellent targets to anti-tank and anti-personnel guns and tactics. WEST BEACH POSITIONS. The defenses of the West Beaches were probably more extensive and elaborate than East Beach defenses.' Airfield No. 1 permitted these defenses to be 700 to 1400 yards deep giving considerably longer fields of fire and permitting a more elaborate system of dummy positions fronting the actual main positions and designed to draw our preliminary bombardment. The terrain was much more substantial for caves and underground 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 slopes which guarded the approaches to Mt. SURIBACHI. It consisted of a maze of concrete pillboxes, bunkers, shelters, and blockhouses which were capable of all-around de­ fense and were mutually supporting. In addition to this elaborate surface organ­ ization, there was an equally elaborate subsurface organization of shelter, passage­ way, living quarters, storage areas, and cave-type firing positions which provided adequate protection against the heaviest of bombs and shells. The excellent ob­ servation from the heights of SURIBACHI and the high ground around Airfield No. 2 were the feey to controlled artillery and mortar fire,

MAIN DEFENSE BELT Since landings in strength were limited to the east and west beaches near the southern 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 western beaches, it stretched east across the island to skirt the southern end of Airfield No. 2, and terminated in the cliffs which form at the northern end of the eastern beaches. The center of this belt was 2600 yards deep. It gained its strength from its depth and its concrete and steel structures, positioned so as to obtain long fields of fire which were carefully calculated and tied into the overall defense system. Reliance on caves as a shelter and a fighting position was increas'ed here. Most of the positions showed excellent engineering and terrain appreciation. Com­ munications were maintained by trenched wire, radios, and a labyrinth of underground tunnels 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 equipped with lights and telephones. Artillery, including heavy mortars and rockets in and behind this defense belt, could cover most of the beach area. Positions were pro­ vided with complete preregistration data. Strong points were established around commanding ground, Conorete-faced caves and infantry positions in the erosion-made crevices were frequently so close to­ gether that an equally strong defensive position existed only a few yards to the rear or flank. Contact became so close that safety of our own troops prevented use of artillery, naval gunfire, or air support in reducing these positions. One bluff, forming something similar to an amphitheatre, contained two terraces and three tiers of concrete pillboxes and oaves* FINAL DEFENSIVE AREA ' • • North of this cross-island defensive sector, the extremely rough terrain from the coast to 2000 yards inland created a natural defensive area. The number of caves and terrain characteristics somewhat compensated for the reduced amounts of concrete and steel. These features, coupled with the masses of men employed, tended to 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 crevices in the rocks and so dispersed as to give an all-around interlocking defense to each small compartment. Attacking troops frequently were subjected to fire from flanks and rear more than from their front. It was always very difficult and frequently impossible to locate exactly where defensive fires originated. In defending IW0 JIMA, the Japs employed one basic tactic which in a sense was a departure from the Japanese defensive operations hitherto generally encountered. This tactic was simply to occupy previously determined D-Day positions and maintain them, without recourse either to costly rtmain effort" counterattacks or organized withdrawals. This plan was not only simple in conception but in general was skill­ fully executed and well adapted to the terrain of IW0 JIMA. There were no organized attempts made to counterattack our beachhead, no large scale night counterattacks, no "all-out" banzai charge. Instead, the enemy committed a minimum number of troops to the southern beach area and defended it by delivering heavy volumes of fire from both 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 most heavily fortified part of the island. The enemy, by continuing to follow his simple but basic defensive tactic of occupying a position and refusing to yield until dug out and killed without counterattacking and without withdrawing, was able to main­ tain organized resistance for over twenty days. There were no tactical withdrawals, no retrograde or delaying actions in the military sense, though in some instances isolated withdrawals were made to preserve units and individuals threatened with inevitable destruction. It is now known that this defense of holding to the end without counterattack or withdrawal was the express plan conceived by the Commanding General. It was this simple tactic, coupled with the incredible rocky terrain and the maximum use the enemy had made of this terrain in constructing fortified posi­ tions 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 the loose sand seriously impeded the movement of even full-tracked vehicles. Anti-tank guns, mainly the high velocity 75 mm and 47 mm, were the principal weapons employed inland. Many anti-tank guns had one or more supplementary or alternate positions* These weapons were sited in terrain affording fields of fire covering possible tank routes from the beach; however, considerable emphasis appears to have been placed on locating an emplacement where it was protected by an abutting bluff or terrace, which shielded it from frontal flat trajectory fire. BLOCKHOUSES AND PILLBOXES Blockhouses and pillboxes near the beaches on the more open terrain were almost invariably sited for flanking fire. Wherever possible, a pillbox was behind a natural mound 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 pillboxes to offset the restricted field of fire of each weapon. Many blockhouses near the beach had sand piled as high as 50 feet in front of them. A narrow fire lane through the sand revealed the direction of fire, but many positions were so well protected that they were still firing until reduced by in­ fantry. Pillboxes were protected similarly; infantry commanders often found it necessary to request main battery fire from naval vessels when secondary battery fire 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 rough terrain, size of the island, and fixed nature of defenses probably account for the limited number. Their manner of employment was as an anti-tank weapon. They were used in support of the main cross-island defense belt either in a revetment or be­ hind protective terrain, camouflaged and stationary. Their 37 mm, 47 mm, and 57 mm guns fired anti-tank and personnel missions like the many 47 mm guns. Reports in­ dicate small tank units were to be employed to support local counterattacks. There is little evidence they were so used. The torn up condition of roads and constant artillery fire may well have prevented any movement. ARTILLERY Artillery tactics were characterized by good observation and careful preplanning of fires. Range stakes were found in the vicinity of landing beaches. The elaborate casemated structures in which artillery pieces were housed, the cave positions from which mortars and rockets were fired, operated to limit the number of pieces which could 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 which we mass artillery fires. Dual purpose guns were used to fire time fire over our troops* An artillery group gave coordination to all field artillery and mortar employ­ ment; coast defense and AA artillery were not included in this command. Mortars had 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 sector infantry commanders. The principal locations of mobile artillery were in the higher ground north of Airfield No. 2 with forward OPs in prominent elevations along the main defensive belt. There definitely were more weapons at the disposal of commanders than were organically assigned to the units. The fixed nature of the defenses permitted personnel normally used for ammunition carriers and for the movement of mobile weapons to be employed to man additional weapons added to basic tables of organ­ ization.

MORTARS AND ROCKETS Although approximately twelve 320 mm spigot mortars were encountered on the island, their effectiveness is doubtful. Emplacements were well constructed and concealed but only a few rounds were fired. IWO's terrain was suited for the use of the many 150 mm, 81 mm and smaller mortars found there. Ammunition was stored throughout the northern half of the island in caves and hasty firing positions were utilized at the entrances. The 150 mm mortars were used to fire on landing beaches. These weapons and the smaller mortars were withdrawn as the situation demanded. Three types of rockets were used as artillery weapons. Several positions were sighted for firing at ships approaching close to shore. The V-trough launcher was used for 63 kg and 250 kg aerial bombs with rocket motors providing the propelling force. A 200 mm rocket was used from a mobile-type launcher and a launcher which is mounted on a mortar-type bipod. Rockets were dispersed in deep draws over the north­ ern portion of the island and the launchers could be moved to the site of the am­ munition.

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It is evident that little was left undone by the Japs in constructing as for­ midable ground defenses as possible on an island with the size and particular terrain of IWO JIMA. A study of Japanese defense installations encountered in the field is presented with photographs and drawings on the following pages. 4—I 1 1—|— 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 RJI06 IS IN TARGET SQUARE 132 A

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

THOUSANDS OF CAVES USED FOR DEFENSIVE POSITIONS, PERSONNEL , AND STORAGE HAVE R S­ T NOT BEEN PLOTTED. '20,000 SCALE IN YARDS W X I Y

JICPOA L-50608-54 - A I B C:D E + A B MAP APPENDIX CINCPAC-CINCPOA BULLETIN NO 136-45 LJ

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IWO JIMA

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 750-709 RJI0 6 IS IN TARGET SQUARE 132 A

BLOCKHOUSES

P Q ; R WITH PRINCIPAL DIRECTIONS OF FIRE INDICATED

Y ­ U V ! W ! X Y W ! X I—I—l

=20,000 Y ­ U V SCALE IN YARDS I I 1 I—H I 1 I

JICPOA L-50608-54 h—•+ 1 h I V 1 B . C D A B C D E MAP APPENDIX CINCPAC-CINCPOA BULLETIN NO 136-45 LJ

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WO JIMA

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 R S : T 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 750-70 9 RJI0 6 IS IN TARGET SQUARE 132 A

ANTI-AIRCRAFT DEFENSES

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JICPOA L-50608-54 I—»——t—I—I—I—I—I—I A B C D A B [ C j D E MAP APPENDIX CINCPAC-CINCPOA BULLETIN NO. 136-45

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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 750-709 RJI0 6 IS IN TARGET SQUARE I32A B C D A B C D

COVERED ARTILLERY

WITH PRINCIPAL DIRECTIONS OF FIRE INDICATED Q R S LEGEND U V W X ALTERNATE POSITION V W X HT SUPPLEMENTARY POSITION

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JICPOA L-50608-54 'T­ r 17' IS1 I4I°2O' 21'

CONFIDENTIAL MAP APPENDIX CINCPAC-CINCPOA BULLETIN NO 136-45

ARCS OF FIRE FOR CASEMATED COASTAL DEFENSE GUNS -49 ' ON 49' IWO JIMA

PLOTTED FROM GROUND STUDY AND CAPTURED MAP

24° 48'

-47' 47'­

46'

195

45' 45'­

17' 18' 19' 141 20" 21'

JICPOA L-50608-5 5 Cleared of mines, . t theshoulders and of road is still mined Extent of field not > nown flints are. 3•"•*"'tf6 ' s//Us iv/ vc/sficM r) 6 mines removed

Single nbrn nemispnencai 252 253 arid bombs reported in Underermine mines Box, area. 3-/0-45 stick mines

This area (qpproK 100 yds square w of rood) onrained 6 Herr, mortar grenod and 53 icol mines. (-5!Magnetic mints armed 27-45 See In&drt £ (H Cosi of flares. d caps / ammo (3) Toot-measure

ry of mined area baHelit p. fuzes (4! BOA /nines remove c i3>Shape charge (I) STjck qrenade .^r tz) s' Duds, 1 nest Tieiqsconrained a i (i) &UA mines and (21) Taoe-ape-neatMeasure vre // were removed 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 mines 250 kg bombs iv ydstick !3) Rows / Hi rn /nrnes mines «? rows removed. /orf. her we en rows 411 removed. This field consisted of 4 ros or mines running approxu parallel to the beach for i distance of over 1000 yar minat, road bl The mines were 63 kg e measure mines Pattern of mines Removedjs) loolb Sombs e)Tonh mines Magnetic Anti- Tank This oreo conrained 57 Co/, 2) $o kg bomb a Trench and 19 Hemispherical mines charoe arena cm 2"Terrace wen si I raws ... to the beach on Horn rninee, ydst cM mines, Tape measure Terrace. The rows mines \yAnfi-p sonnet, ZSaparT, Double and si Removed (2*) Ant, a. horned mines were fovn nvasioni Horned) mine Some irunm Mfrnp-Hind son contdbieci scrfetf-pi Tbe\ Conicalmin?S-w 3 rowi(f'f&rrace) onk £ ro (2 terracer),' stoy$t*4di it rt beach and 25'apart ' Hoi were present for additionc 63'j kgbombs, \yydstic Removed (eto mines OneDepth charge box mine.5 found-(See insert f'J.3/

/tasty mine fie JLXtll), This area contained 4 yds tic A f 3 oito mines removed. 3 3 in series of 2 with horn mines i row ac'ft off connecfing. a// , a/so rape-measure,

nsert G" do/ mines I claare 60) Kg be •nbs remoireo' 3-i-fS rows Tort ap 20 ft apart. Pattern of mines This area contain C) Incendi ary re. voved. 3-3-45 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 ((» US A'oyy gun firs of (6OJ US mcrfor duds Mined area has bee neutra/jze d of IS) VS. Novy rocket- Bomb Disposal Co.

(4) AP mines ItS . (/'/) fr mines '3) Jnp flora 11 HI Florns L 1 wmmmm•1 0 500 1000 2000 yds

JICPOA L- 50608-56 CINCPAC-CINCPOA BULLETIN NO. 136-45 MAP APPENDIX GENERAL TERRAIN FEATURES -Beoches

Amphibious tractor stuck In loose sand on East Beach.

Deep footprints indicate loose character of sand on beaches. Beaches

Marston matting on East Beach essential to vehicular movement over the soft sand.

Bogged down Jeep with chains on East Beach subsequently damaged by enemy fire.

8 Beaches

Wave-cut terrace on East Beach.

Terrace on East Beach and amphibious tractor. Beaches

Steep gradient of beach com­ bined with looseness of sand made movement difficult for" vehicles and troops.

View of terrace Just inland from Blue Beach #2.

10 Terrain Inland

Looking west. This Is a typical area inland along the West Beach. (TA-163J)

Clumps of vegetation in the central areas con­ cealed trenches, rifle pits and MG positions. Terrain Inland

Covered artillery posi­ tion housing 47 mm AT gun firing down runway of #2 airfield. Type of terrain in which gun emplacements were least vulnerable to naval gun fire. (TA-183C)

Areas of this sort pro­ vided excellent cover to the enemy in his attempts to infiltrate our lines. (TA-E33M)

12 Terrain Inland

Approaching Hill 362 show­ ing the natural rugged terrain which confronted troops. Since troops could advance here only with great difficulty, this terrain was a decided asset to the enemy. (TA-216N)

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

13 Terrain Inland

m

Looking south showing the rugged terrain approach­ ing Mt. Suribachi. (TA-132R)

This picture is typical of cave-infested north­ ern area terrain. (TA-234D)

14 Terrain Inland

Rocky outcrops and scrub vegetation characteristic of the northern one-third of the island making move­ ment of troops difficult.

Rocky terrain near north coast provided the enemy with natural positions for MGs and riflemen.

15 Terrain Inland

- *

View of terrain typical of that encountered In vicinity of Hill 382. (TA-200Y)

Trench cut through reck leading to gun positions near East Boat Basin. (TA-166D)

16 OBSTACLES AND MINES- Mines

Close-up of taried oil drum with the top cut open and ready for land- mine to be emplaced. Due to the enemy's dis­ rupted schedule caused by cur bombing prior to D day, they did not have time to set up the mine field in conjunction with the oil drums. (TA-180X)

View of West Beach showing 55-gallon oil drums which were to be used as land mines. Electrically con­ trolled mines were to be put into the drums to hin­ der our landing on this beach

17 Mines

250 kg bomb burled in sand as land mine. These mines were fuzed with yardstick mines Placed on top of the bomb and secured in Place with fine wire. Many such mines thus employed were located strategically, and well covered with fire from AT weapons. (TA-165 0)

View of the West Beach showing one-horned coni­ cal land mines. The entire West Beach was mined.

18 Trip Wire

Trip Wire. (TA-201S)

This was the only evidence of trip wire or barbed wire being used in this area. It proved ineffective In stopping troops from land­ ing 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 series of caves leading off in different directions and connecting with other caves In the near vicinity. Food, ammu­ nition and .clothing were found In these caves indicating troops had been quartered there. (TA-199U)

Interior view showing steps leading out of the cave which is about forty feet under ground with large rooms throughout for the quartering of troops. (TA-199U)

21 Caves

Typical entrance to ex­ tensive cave network, extending from under­ neath the quarry near the East Boat Basin with tunnels leading as far bs 800 yds. to Minami Village. (TA-183W)

Entrance to cave (TA-198X)

22 Caves

Interior view of exten­ sive cave•network under CD gun over East Boat Basin. (TA-183X)

Entrance to cave. (TA-216D)

23 Coves

One of many caves In for­ ward slopes of hills guarding airfield No. 2. MGs and small arms fire was received from these positions which provided excellent observation of the entire East Beach area. (TA-183H)

Interior view of cave showing steps leading down and passageway leading off to either side where troops were 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 by naval gun fire. Reinforced concrete 4 ft. thick. En­ trance to these casemates Is In the rear connected by- cave networks which were used as personnel shelters, food storage and ammunition storage. These guns were set about 15 yds. apart and had a field of fire cover- Ing the entire West beaches and areas out to sea. (TA-216D)

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

26 15 cm CD GUNS

Front view of blockhouse housing a 155 mm (15 cm) CD gun. Destruction caused by naval gun fire, Entrance Is in rear of blockhouse with adjoin­ ing caves throughout for personnel shelter, food storage and ammunition storage. (TA-216D)

Rangefinder placed between two CD guns in same area used as part of fire con­ trol equipment. (TA-216D)

27 15 cm CD GUNS

Rear view of 155 mm (15 cm) CD gun In blockhouse showing destruction caused by naval gun fire . (TA-216D)(SW)

Ruins of casemate contain­ ing 155 mm (15 cm) CD gun, Two such Installations, built of reinforced con­ crete with walls over 4 ft. thick and connected with rangefinder and OP, were located on the edge Of a cliff at TA-219A.

28 14 cm CD GUNS

View of cave entrance leading from casemated 140 mm (14 cm) CD gun back. Into the base of the crater. (TA-132L)

Breech-block view of one of the 140 mm (14 cm) guns at the foot of Suri­ bachl showing destruc­ tion. It is known that "these guns were silenced prior to our landing but ruins of these installa­ tions provided cover for the enemy and afforded an opportunity to inflict casualties on troops ad­ vancing toward Mt. Suri­ bachl. (TA-132K)

29 14 cm CD GUNS

Front view of one of the 140 mm (14 cm) CD guns showing destruction caused by naval gun fire (TA-132K)

Front view of one of the 140 mm (14 cm) CD guns casemated at the foot of Mt. Suribachi. They were constructed of reinforced concrete about 4 ft. thick with tunnels lead­ ing from the rear into the base of the mountain and connecting each in­ stallation. These tun­ nels also connected to personnel shelters, food storage and ammunition storage. (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-foot fire port. This Is one of the four emplacements found at the base of Mt. Surlbachi. (TA-132 K)

31