ARMY UNITS Forward Echelon, 18th Infantry Division--Capt Iki. Advance detachment from most units of the division. Since the 13th Div never reached Guam, the troops were probably attached to 29th Div headquarters units and may possibly be included in totals below
200 Southern Marianas Group and 29th Infantry Division Headquarters--LtGen Takashina. Takashina's command included Guam and Rota plus Tinian after the fall of Saipan. LtGen Obata, 31st Army Commander, was present on the island but did not take over actual control of the defense until after Takashina's death
220 29th Division Signal Unit--Capt Suda. Understrength, like most division headquarters units as some men were lost in the sinking of the 18th Regt transport and others were with the 50th Regt on Tinian which was originally part of the division
186 29th Division Ordnance Unit--Lt Kamei
45 29th Division Intendance Unit--LtCol Mitzutani. This unit handled finance and quartermaster activity and may have acted as the control agency for conscripted civilian labor
133 29th Division Transport Unit--Lt Mori
97 29th Division Field Hospital--LtCol Morimoto
290 24th Tank Company--Capt Sato. Assigned as division tank unit with nine light tanks, eight tanks having been lost in sinking of 18th Regt transport
117 265th Independent Motor Transport Company--Lt Takeuchi. Probably assigned to division headquarters
180 18th Infantry Regiment (minus 1st Battalion)--Col Ohashi. Unit lost almost 50% of personnel and all heavy equipment in submarine attack enroute to Saipan. After reorganization, headquarters and two battalions moved to Guam, leaving 1st Bn on Saipan and tank unit on Tinian. Each battalion had three rifle companies, a trench mortar company, and a pioneer unit
1,300 38th Infantry Regiment--Col Suenaga. Regimental headquarters, signal, medical, intendance, transport, and engineer units. Three infantry battalions, each with three rifle companies, an infantry gun company, and a machine-gun company. One mountain artillery battalion with four companies
2,894 48th Independent Mixed Brigade Headquarters--MajGen Shigematsu. Originally the 11th Div Infantry Group Headquarters which came to Guam in the 6th Expeditionary Force
149 48th IMB Engineer Company--Capt Miyake
187 48th IMB Medical Company--Capt Kitazawa
164 48th IMB Signal Company--Lt Kamakura
109 48th IMB Artillery Unit--Capt Kato. Headquarters and three companies, formerly 3d Bn, 11th MtArty Regt of the 11th Div
368 319th Independent Infantry Battalion--Capt Miyanashi. Formed from the fourth rifle company taken from the three infantry battalions of the 11th Div which came to Guam with the 6th Expeditionary Force
360 820th Independent Infantry Battalion--Capt Nakamura. Three rifle companies, an infantry gun company, and a machine-gun company, formerly 3d Bn, 12th InfRegt of the 11th Div
486 321st Independent Infantry Battalion--Capt Furukawa. Three rifle companies, an infantry gun company, and a machine-gun company, formerly 3d Bn, 43d InfRegt of the 11th Div
488
322d Independent Infantry Battalion--Maj Hamada. Three rifle companies, an infantry gun company, and a machine-gun company, formerly 1st Bn, 44th InfRegt of the 11th Div
500 10th Independent Mixed Regiment (minus 1st Battalion)--LtCol Kataoka. Formed from the units of the 1st Div in the 6th Expeditionary Force. Regimental headquarters, engineer, and signal companies. Two infantry battalions, each with three rifle companies, an infantry gun company, and a machine-gun company. An artillery unit with two companies. The 1st Bn with one artillery company and an engineer platoon was on Rota
1,912 52d Field Antiaircraft Battalion (minus 1st and 3d Companies)--LtCol Ishii. Headquarters and the 2d Company plus the AA unit of the 18th InfRegt
250 45th Independent Antiaircraft Company--Assigned to the 52d FAA Bn
140 1st Company, 9th Tank Regiment--Lt Ko. Twelve to fifteen light tanks, assigned to 38th RCT
122 2d Company, 9th Tank Regiment--Lt Kumagai. Ten to eleven mediums and two to three light tanks, assigned to 48th IMB
122 2d Company, 7th Independent Engineer Regiment
225 2d Company, 16th Shipping Engineer Regiment--Lt Ogawa
200 Detachment, 60th Anchorage Headquarters
20 Total Army2
11,464
NAVY GROUND UNITS54th Naval Guard Force--Capt Sugimoto. Headquarters and 21 coast defense and antiaircraft units
2,300 60th Antiaircraft Defense Unit--Lt(jg) Mochimitsu
259 217th Construction Battalion--Capt Sugimoto
900 218th Construction Battalion
900 Land Reclamation Unit--Mostly Japanese civilian males impressed for labor and lightly armed in the later stages of the campaign
300 Total Navy Ground
4,659
NAVY AIR UNITSGuam Branch, Southeast Area Air Depot
100 263d (Hyo) Air Group--Cdr Tamai. All air groups consisted of ground elements hastily organized for airfield defense
800 521st (Otori) Air Group--Cdr Kamai
400 755th (Genzan) Air Group--Cdr Kusumoto
700 Total Navy Air3
2,000 Total Army (rounded out)
11,500 Total Navy Ground (rounded out)
5,000 Total Navy Air (rounded out)
2,000 Grand Total (rounded out)4
18,500
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Footnotes
1. Figures shown are mainly from IIIAC Final Order of Battle, dtd 8Aug44. Any revisions and deletions have been made in light of intelligence data available following the campaign.
2. The original C-2 figure for Army troops was 12,744, but it included several units that definitely were not present. For example, elements of the 11th AA Regt and the 55th IndEngBn were identified and given a tentative troop strength of 650; however, the first unit was reorganized into the 52d FAA Bn in Manchuria and the second into the 16th ShpgEngRegt in the Philippines. In addition, there is insufficient evidence now to include four miscellaneous units with a total estimated strength of 726 that were carried on the original list.
3. Original C-2 estimate of enemy air unit strength was 600; however, the strength of the three air groups in May 1944 is listed in CinCPac-CinCPOA Translation No. 12,541 as 3,100. Since the only casualties were to flying personnel and those killed in preinvasion bombardments and there is no evidence to indicate that any substantial number of ground crewmen were evacuated, a more reasonable estimate of group strength is included above. Of the original assigned plane strength of 80 fighters and 80 bombers, all were lost, either shot down in dogfights over Guam, demolished on the ground, or missing in battles over Biak Island.
4. The figures have been rounded out to avoid the appearance of exactness, since the strengths of many units are only estimates. In view of the final enemy casualty figures on Guam this figure is, if anything, a minimum estimate.