COPY NO.

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PECIAL ACTIO REPORT

A U CA N LS

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NSEI-SHOTOUNr.lASSIFIED

FIPST MARINE DIVISION30UCE0 BT MAPPING REPRO ON SECTION FIRST ENGINCER ,ON FIRST MARINE DIVISION

1945

01718 1990-5-80 485/390

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F i r s t Marine D i v i s i o n , F l e e t Marine Force, c/o F l e e t Post O f f i c e , San Francisco, CONFIDENTIAL From: To : Via :

California.

10 July, 1945. The Commanding General* Commandant of the Marine Corps* (1) The Commanding General, III Amphibious Corps. (2) The Commanding General, Fleet Marine Force, Pacific. (3) CINCPAC - CINCPOA. Aotion Report, NAN3EI SHOTO Operation, 1 Aroril 30 June, 1945, submission of. P a c i f i c F l e e t Confidential Letter 1CL-45. (A) Subject Report.

Subject; Reference: Enclosure:

In accordance with the r e f e r e n c e , enclosure (A) 1. i s submitted herewith. 2. Each has been forwarded r e p o r t i n order to c o p i e s through the organization shown on d i s t r i b u t i o n l i s t the required number of copies o f subject preclude tne n e c e s s i t y of forwarding a l l chain of command.

P. A. d e l VALLE

DISTRIBUTION: CinC Commander i n Chief, U, S. F l e e t . Commandant of the Marine Corps. CINCPAC - CINCPQA (3) CG, FMF, PAC. CG, 10th Army (2) Commander in Chief, Soutnwest Pacific Areas. CG, V Amphibious Corps

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DECLASSIFIED

Subject: Action Report, NANSEI S O O Operation, 1 April HT 30 June, 1945, submission of. (Con^d). CO, 2d Marine D i v i s i o n . CO, 3rd Marine Division. CO, 4th Marine Division. CG, 5th Marine Division. CG, 6th Marine Division. Commander Third Amphibious Force. ANSCOL. Naval War College. Command and General Staff School. Marine Corps Schools (3) Commander Amphibious Training Command Pacific. Commander Amphibious Training Command Atlantic. Commanding General Troop Training Unit Pacific. Commanding General, Training Center, Fleet Marine Force, Camp Lejeune. Commanding General, Training Center, Fleet Marine Force, Camp Pendleton. Commander Third Fleet. Commander Fifth Fleet. CO, 8th Marines. CG, XXIV Corps. CG, 7th Infantry Division. CG, 77th Infantry Division. CG, 27th Infantry Division. CG, 96th Infantry Division.

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TABLE of CONTENTS Special Action Report Nansei Shoto Chapter Chapter I - Introduction II - Task Organization

Chapter III - Preliminary Planning Personnel Annex Intelligence Annex Operations Annex Supply Annex Medical Annex Chapter Chapter Chapter IV - Training and Rehearsals V - Loading and Embarkation VI - Movement to and Arrival at Objective Area

Chapter VII - Assault Phase Narrative Division Field Orders Tank Support Annex Artillery Annex Naval Gunfire Annex Air Support Annex Signal Annex Engineer Annex Logistics Annex Shore Party Annex Medical Annex Personnel Annex Chapter v m - Intelligence Chapter Chapter IX - Operational Results X - Comments and Recommendations

DECLteSfflED

CHAPTER I ; INTRODUCTION SPECIAL ACTION REPORT -NANSEI SHOTO

INTRODUCTION Special Action Report Nansel Shoto Operations of the First Marine Division (Reinforced) against the former Japanese island of O I A A are divided into three KN W Phases for purposes of this report: Phase I included training, planning and rehearsals conducted in the RUSSELL ISLANDS, G A A C N L Area. The movement UDLAA of t h i s Division to the target area concluded Phase I . Phase II began with the assault ship-to-shore movement on 1 April. 1945. Ground action in Central and Northern O I A A was included in t h i s phase which terminated on 22 April, 1945. KN W Phase I I I consisted of the battle for Southern OKINAWA the final destruction of organized resistance on the island, and the mopping up of enemy remnants. Phase III was o f f i c i a l l y terminated on 30 June, 1945. Phases I and II of First Marine Division operations on O I A A KN W provide few lessons for future study that may be included in an action report. The primary reason for this i s that the negligible enemy resistance i n this Division's zone of action provided few opportunities to discover the strengths and weaknesses of a combat organization. Weapons and equipment were not tested under conditions which would warrant qualified opinions on their e f f e c t i v e n e s s ; the only t a c t i c s employed were previously time-tested; and the lessons from Japanese t a c t i c s were almost completely non-existent* I t was during Phase III that the efficiency of this Division was tested and proved. In the protracted, fiercely-contested b a t t l e for Southern OKINAWA, valuable lessons were learned. I t i s the purpose of t h i s report to oroject these lessons against a background of the action as i t developed. While basic doctrine i n a l l cases was again oroved sound, i t i s necessary to point out the application of t h i s doctrine i n s p e c i f i c situations. Pertinent narratives, comments, and recommendations are grouped in the following chapters. Before the detailed operations of the First Marine Division can be analyzed, i t i s well to putline the over-all role played in the invasion of the NANSEI SHOTO. The task of the newlycreated U.S. Tenth Army and supporting units of the Unites jttffes

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UNCLASSIFIEDFleet was to continue the growing assault on the inner defense lines of the Japanese Empire and to secure naval and air bases for further blows against the enemy* Capture of principal islands in the NANSEI SHOTO would provide these bases and secure a r a sage to the China Seas, the coast of China, and the approaches to the Japanese mainland* As a part of this army, it was the mission of the First Marine Division, functioning under the control of the III Amphibious Corps, to defeat the enemy in its zone of action and be prepared to carry out any further assigned operations. The Division's initial assignment consisted of landing on the west coast of OKINAWA and driving to the opposite coast on a proposed timetable of fifteen days* As the action unfolded, initial successes came with surprising ease. Central and Northern OKINAWA fell quickly to Tenth Army forces* Major Japanese defenses were located in Southern OKINAWA: in that area the decisive battles of the island were fought* The following chapters record the part played by the First Marine Division in seourlng vital OKINAWA. The results of this experience are incorporatea for the future benefit of those who participated in the campaign and for those who may be faced with comparable situations in the future*

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...CHAPTER IE... ..TASK ORGANIZATION... SPECIAL ACTION QE1POQT ...NANSE1I SWOTO...

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UECmSIFltDTASK ORGANIZATION Special Action Report Nansei Shoto CT - 1 lBt Marines Co A let Engr Bn Co A 1st Plon Bn Co A 1st Med Bn Co A 1st MT Bn Det Ord Co 1st Serv Bn Atchd: 2d Plat, 1st Bomb Disposal Co (less 2d and 3d Sqds) Det S&S Co 1st Serv Bn 1st Plat 1st MP Co Det 4th JASCO Det 454th Amph Trk Co (Army) (3 DUKW) CT - 5

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Many of these men, were deserving of promotion for creditable performance in combat0 After OKINAWA^ there-will once again exist the problem of necessary officer and enlisted rotation* Present survey indicates there may remain 205 officers of various ranks having twentyfour or more months overseas as of 30 June, 1945 Over half of these will have over thirty months9 There will be approximately 3,200 enlisted with two years or more in the field, of which nearly 800 will have thirty months. As the fall of 1945 approaches the situation will become more acute from the morale viewpointp,inasmuch the personnel entering the two-year category will have spent their entire tour in cocoanut grove or Jungle with not a single opportunity for leave or liberty,,

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INTELLIGENCE Special Action Report - NAN8EI SHOTO Prior to landing on OKINAWA 3HIMA this Division oonduoted a vigorous and comprehensive training and planning program. The part played by the Division Intelligence Section consis ted of conducting a school to train and Instruct Intelligence personnel in their duties* Instruction was given in the functions of combat intelligence, beach reconnaissance, and Japanese language; regimental and division field exercises were carried out. Schoolst An intelligence sohool for the enlisted personnel of the various intelligence sections within the division was con ducted by the D-2 section from 12 Deo ember to 5 January* It's main aim was to present a baslo understanding of the organ ization and function of intelligence agencies and the indiv idual duties required of all such personnel* The training was particularly adapted and well timed* since a large number of new men had entered the D-2 section and were in need of such instruction* Among the variety of courses offered; certain ones of basic importance were stressed* They were as follows: Map reading and orientation. Use of the compass and azimuth hikes* Panoramic and planemetrlc sketching* Construction and purpose of observation posts* Form for and use of Periodic Report, Work Sheet, Journal, Intelligence Plan and Annex* (6) CP procedure* Practical work in the field included CP procedure and the function and organization of its various component parte. One night was devoted to a compass march without benefit of light, to test the ability to work under handicap and to further facilitate the use of the compass* At the conclusion of the school, a Division CPX was held allowing each enlisted man to perform the duties ft*"^3^1! R-2 and- D-2, ,of ,the .division. fl L F 1 -* i ^ ' \1)

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During each CPX, time was allowed for instruction and operation of radio sets, A radio school of one week's dur ation starting 12 January, 1945 was conducted by the Signal Company for all Division Intelligence personnel, in which the complete operation and function of the SCR-300 and 610 radio were explained in detail. The purpose of the D-2 net was given special consideration, A Beach Reconnaissance School was held from 7 January, 1945 to the 26th by the D-2 section. Representatives of the 2-sections throughout the Division were required to attend* Instruction in hydrographic reconnaissance, API, photography, rubber boating and range estimation was featured* This type of training was undertaken in view of the probable necessity of euch reoonnale sanee on the Impending operation. The work of the Navy UDT was fully explained so as to coordinate the two functions later on. Practical exercises in water borne reconnaissance from the reefs edge, was practiced on nearby islands and complete photographic coverage of the landing beaches obtained. The results of the above training has now become self evident. Eleven lectures ranging from one to two hours on combat phrases, pronunciations, simple vocabulary, numbers, geo graphical terms, and dates were given by officers of the language section to the Reconnaissance Company; enlisted intelligence personnel of Division Headquarters and separate battalions; enlisted personnel of 5th and 7th Marines R-2 sections; "E*, "P-, and "a" Companies, 2nd Battalion, 5th Marines; 1st Tank Battalion; and General Duty and Band personnel of Headquarters. A syllabus was given to each of these groups to supplement the lectures. These lectures were given between 28 November, 1944 and 15 February, 1945 Three courses of a similar but more detailed nature were also given by personnel of the language section be tween 8 December, 1944 and 16 February, 1945, as follows: (1) Five weeks oourse to the MP Company l hours a day, five (5) days a week with speolal emphasis on vocabulary for handling of PWs around the stockade and on working parties* A twelve (12) page syllabus was supplied with the course. Five weeks course to the Red Cross Service Center

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with special emphasis on combat phrases. The syllabus used in the eleven lectures and some add itional pages were supplied with this course. (3) Three (3) weeks course to the Medical Battalion one (l) hour a day, four (4) days a week with special emphasis on medical vocabulary. The MP syllabus and some additional pages on medical terms were used as a basis. During December and January a training film on combat phrases was shown at the various movie areas, and a combat phrase was published each day for about a month in the Pavuvu Press after the middle of January. On 23 February, 1945 fifteen (15) sets of combat phraser cartoons such as were used prior to the PELELIU Operation, and 10,000 cards containing thirty-six (36) phrases were distributed to the various front line units of the Division, Indoctrination material concerning the handling of PWs end captured materiel was presented in all the lectures and courses mentioned above. In addition, one to two hour lec tures on these subjects alone were presented to the enlisted intelligence personnel of the let Marines; the R-2 personnel of the 7th Marines; and the enlisted intelligence personnel of Division Headquarters Bn and the separate battalions. These were given between 8 December, 1944 and 2 January, 1945 A training film on the handling of PWs was shown to the last group above on 29 Deoember, 1944. Plans to give similar lectures and films to the intelligence officers of the Div ision during January were cancelled because of the absenoe of various regiments on training programs. Special training of language personnel. After the PELELIU campaign it was decided to send the members of the language section to JICPOA for further training in trans lation and interrogation in order that the officers and men should not stagnate between operations. It was planned to leave two officers and one enlisted man behind for admin istrative and training purposes and to rotate them with two others at a later date. The time element prevented the carrying out of the second part of this plan, but eleven (11) offioers and ten enlisted men (including one each from the MP Company.the 1st Marines, and the 5th Marines) left for

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PEARL H R O on 17 November, 1944, while one o f f i c e r en route ABR baok from eeoorting a group of PWe from PELELIU to the Main land arrived at FMF, Pao. on 16 November, 1946*and vafi a s s i g n ed to the same type of duty as the others assumed upon t h e i r arrival* All personnel returned to the Division between 17 January and 15 February, 1946 Suoh training was found to be invaluable to both o f f i c e r s and men, and a greater effort to have a l l personnel participate in t h i s training between future operations i s recommended*

Because liaison teams from the Division Intelligence Sec tion proved to be of so much value during the previous oper ation, it was decided to employ them again. Great profit was derived from the lessons learned on that operation and a period of intensive training was undergone by the officers and men chosen to form the teams. A uniform procedure for reporting to Division, adjacent, and lower echelons was care fully worked out; printed forms for the making of written reports were printed and distributed to the officer in charge of each team; instruction was given in telephone and radio procedure; and each team was carefully briefed and instructed in its primary function, which was to make detailed periodic reports to Division and to keep a constant stream of infor mation flowing to Division and adjacent units. After a period of training had been successfully brought to a close, the Division Intelligence Section immediately set to performing its functions in preparation and planning for the coming operation. It concerned itself with the procurement, study, and distribution of aerial photographs, and maps, including relief maps. An Intelligence Estimate and an Enemy Order of Battle were prepared. Personnel were briefed, and the Division Intelligence Section was carefully organized to perform its duties during the operation in the most efficient fashion. Photographs: Photographs of the target area were furnished entirely by JICPOA, distributed chiefly through the III Amphibious Corps. The following sets of photographs were regej^

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Date Rec'd 27 Dec 44 27 Deo 44 28 Deo 44 9 9 9 5 8 Jan 45 Jan 45 Jan 45 Feb 45 Feb 45

Type Obi. Vert. Vert. Vert. Vert. Vert. Vert. Vert. Vert. Higi A l t . Obi. Vert. Vert. Vert. Vert. Vert. Vert-. Vert. Vert. Vert.

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1:12,300 1:15,500 1:5,000 1:5,000 1:10,000 1:11,000 1:6,000 1:6,000

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22 Jan 45 22 Jan 45 22 Jan 45 22 Jan 45 22 Jan 45 22 Jan 45 3 Jan 45 3 3 Jan 45 Jan 45

14 Feb 45 16 Feb 45 17 Feb 45 17 Feb 45 17 Feb 45 20 Feb 45 25 Mar 45 25 Mar 45 5 Mar 45

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Photo coverage varied from poor to excellent but cover age capable of Interpretation was limited to approximately 5,00 yards inland, from the landing beaches and a narrow s t r i p along the opposite (East) ooast which included the en r. t i r e uifjagtf HANTO. ^*>;f&W3, to aid in control, and confirmed its plan to assist the Sixth Marine Division in the capture of YONTAN k%vtV^d ;t v rto* IJhdj ' *jufrt North of ouavZoine b%fAgtoiafy*.*; *\\ 1 ' *' -f. -'it J i - > . .v

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Tentative S'irsi, Marine Division Operational Plan 1-45 was complexed on 2 February, but It had to be held up for slight revisions on receipt of tne Corps oraer. The plan was issued on 5 February and on that day operations officers from all units were briefed by G-3, Earlier, regimental and some separate battalion commanders had been briefed as information became available. About this time dissemination of information to lower units began to enable them to initiate detail planning This Division, embarked on TransRon 18 with the CP aboard the US3 BURLEIGH, continued planningwith only minor changes throughout rehersals and the approach to the target area.

SUPPLY ANNEX Special Action Report NANSEI 3H0TC The Division returned from the PALAU Operation in three echelons, the last of which arrived at the rehabilitation area in mid-November < Reequipping did not commence as soon as had , been desiredo Reequipping proceeded at a satisfactory rate0 However, as in the past, the Division wan still receiving equipment and supplies after transport and LSTs had been loaded. This was particularly true in the erase of signal supplies0 Prior to embarkation, orders were received to embark ninety days signal supplies replenishments instead of the customary thirty days replenishments,, This necessitated shipping bf air to the serving depot many signal supply items In order to meet the n required deadline Steps were initiated early in the reequipping phase to obtain fifty-five gallon water drumsc Previously, used petroleum drums had been cleaned and sterilized and then used as water containers This method was entirely unsatisfactory and the problem of embarking five days water was solved by the use of the new type galvanized water drum0 During the reequipping phase, full cooperation in all supply matters was received from the Fourth Base Depot This contributed immeasurably to the high state of equipment readiness of this Division for the OKINAWA Operation0 Logistical planning was based on two premises? first, that landing beaches would be strongly defended, and secondly, that the enemy would contest our advance determinedly from his positions in the advantageous terrain. For this reason, it was decided to land only dpeclfied amounts of high priority orargo during the first dayQ High priority cargo Included one unit of fire for all weapons, one days' rations, one days0 water, sufficient fuel for tanks, DUKW's and LVT's, necessary medical and signal supplies, fortification materials and demolitions0 Priority cargo LCVP, LOK and LCT loads were drawn up and presented to the Navy for final approval. This plan, known as the, "hot cargo" plan, was then embodied in CTF 53o2 Attack order0

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The OKINAWA Operation was similar to the PALAU Operation in that a fringing reef off the landing beaches would be encountered and that a reef-transfer line would have to be established, utilizing swing cranes on pontoon barges for transferring cargo from shlpns craft to LVTs and DUKWso Therein, all similarity between the two operations end.ed0 In the planning phase it was apparent that after beachheads had been secured the problems of tactical and logistical motor transport imposed by operations on a large land mass . over a poor road net would be encountered,. It was decided that all available shipping space should be utilized to transport Division organic motor vehicles to the Target Area0 Logistical planning for the OKINAWA Operation was simplified due to the fact that all units would be mounted from either PAVUVU or BANIKA in the RUSSELL ISLANDS,, No complex movement of ships to various mounting out areas was encountered which greatly facilitated embarkation and loading

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MEDICAL ANNEX Special Action Report Nansei 3hoto MATERIAL Upon return to PAVUVU from the PALAU Islands It was necessary to reequip the medical department with many units which had been lost in action0 Approximately one-half of all medical units were lost in the PELELIU operation. The Medical Supply Facilities at GUADALCANAL and ESPIRITU SANTOS gradually supplied most of the necessary equipment and supplies to bring all medical activities up to standard strength,, In many cases, due to shortages at nearby medical supply facilities it was necessary to request supplies from PEARL HARBORo The fault seems to lie in lack of coordination between the various supply facilities. Empty First Aid Jungle Kits for most all combat troops were available, but there were no supplies with which to equip them, e 0 g 0 , no vials for salt and Atabrlne tablets and no bottles for fungicide solution. Such a situation is regrettable because the^e kits were used both at CAPE GLOU CESTER and PELELIU and were found to be far superior to the standard first aid packet. Approximately 7000 were equipped by utilizing such containers as could be procured by devious mean So Efforts were made to obtain adequate supplies of medi cinal Brandy0 In combat, brandy has been found to be very valuable in the treatment of combat fatigue, shock and ex posure cases. However, due to disapproval of requisitions by higher medical echelons, an adequate supply could not be obtainedo Plans were made to make extensive use of serum-albumin in accordance with numerous directives from the Bureau of Medicine and Surgery,, All supplies and equipment not carried by combat units were dispersed for transportation to the five medical com panies.

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SANITATION Three sanitary squads were trained to operate with each combat team to spray DDT on all bodies and assist in mosquito and fly control. On previous operations these squads had proven invaluable Their work was to be later supplemented by the Malaria Control Unit. Prefabricated seats were prepared and issued to all units for use on emp ty 50 gallon drums as latrines. Each drum was to be buried to about 3/4 of Its height and the seats close fitting to avoid entrance and egress of flies. It was believed that these fixtures would keep all the usual gastro-intestinal diseases at a minimum. These drums also were to have 5 gal lons of DDT in oil added to them before use. All units were fully instructed in the value of sani tation while in oombat. PERSONNEL Each combat team was assigned litter bearers for each rifle company to evacuate casualties from the front lines to aid stations. These litter bearers were trained in first aid and the evacuation of casualties* Each infantry battalion had 40 hospital corpsmen assign ed, permitting t he use of two corpsmen to each platoonB All medical personnel were brought up to authorized strength.

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-CHAPTER BE TRAINING # REHEARSALS SPECIAL ACTION REPORT -IMANSEI SHOTO

TRAINING AND REHEARSALS Special Action Report Nansei Shoto TRAINING

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