1. This chapter was originally prepared in Japanese by Col. Ichiji Sugita, Imperial Japanese Army. For duty assignments of this officer, cf. n. 1, Chapter VI. All source materials cited in the chapter are located in G-2 Historical Section Files, GHQ FEC.
2. Enemy air strength in June 1943 was estimated at about 350 planes in the Guadalcanal area, and another 350 in eastern New Guinea. (1) Nanto Homen Sakusen Kiroku Sono San: Dai Juhachi Gun no Sakusen (Southeast Area Operations Record, Part III: Eighteenth Army Operations) 1st Demobilization Bureau, Sep 46. Vol. I, pp. 139-41, 156-7. (2) Nanto Homen Koku Sakusen Kiroku (Southeast Area Air Operations Record) 1st Demobilization Bureau, Sep 46, p. 14.
3. Aerial reconnaissance of the Bena Bena and Hagen areas in the middle of June revealed the existence of seven large enemy airfields, two of which were still under construction, two medium fields, and three small dispersal strips. Southeast Area Operations Record, Part III, op. cit. Vol. II, pp. 5-6.
4. Estimate of enemy situation and intentions given in preceding paragraphs is based on memoranda-notes kept by the writer, at that time Staff Officer (Intelligence Bureau), Imperial General Headquarters. Additional data on the enemy air situation based on reference given in n. 2.
5. In addition to enemy interference, shortage of transport shipping was a major difficulty. Combined shipping available to both Eighth Area Army and Southeast Area Fleet at this time was broken down as follows: Large transports, 15; small transports, 40; powered sailing vessels, 80; fishing boats, 180; powered sampans, 235; large landing barges, 400; collapsible boats, 100. (1) Writer's memoranda-notes; (2) Statement by Capt. Toshikazu Ohmae, Staff Officer (Operations), Southeast Area Fleet.
6. Goals fixed for the end of 1943 were total self-sufficiency in the Solomons and New Britain, at least 50 per cent self-sufficiency for the Madang and Wewak areas in New Guinea, and 25 per cent for other New Guinea areas. Nanto Homen Sakusen Kiroku Sono Shi: Dai Hachi Homen Gun no Sakusen (Southeast Area Operations Record, Part IV: Eighth Area Army Operations) 1st Demobilization Bureau, Jul 49, pp. 100-1.
10. At this time the Eleventh Air Fleet had an operational strength of approximately 300 planes of all types. Nanto Homen Kaigun Sakusen Sono Ni (Southeast Area Naval Operations Part II) 2d Demobilization Bureau, Feb 47, pp. 14-5, 18-9, 26.
11. The Eighteenth Army plan envisaged employing the main strength of the 20th Division against Bena Bena, Kainantu and the Mt. Wilhelm area, and elements of the 20th Division against Bena Bena, Kainantu and the Mt. Wilhelm area, and elements of the 41st Division against the Mt. Hagen area. Ground operations were to be preceded by air attacks to neutralize enemy air bases, and use of airborne troops was also contemplated. All objectives were to be occupied within two to three months from the start of operations in early September. Southeast Area Operations Record, Part III, op. cit. Vol. II, pp. 10-12.
(Statements by Lt. Col. Kengoro, Tanaka, Staff Officer (Operations), Eighteenth Army and Capt. Ohme, previously cited.)
17. These units were the 1st Battalion, 80th Infantry (20th Div.), which had recently arrived from Madang, and the 1st Battalion, 66th Infantry. Maj. Gen. Murotani had replaced Maj. Gen. Okabe as 51st Infantry Group Commander.
23. In June Imperial General Headquarters and Eighth Area Army were still planning to execute the plan for ground operations against the Bena Bena and Hagen areas. Daihonyei Rikugun Tosui Kiroku (Imperial General Headquarters Army High Command Record) 1st Demobilization Bureau, Nov 46. p. 153.
Southeast Area Operations Record, Part III, op. cit. Vol. II, pp. 18-9, 50-2.
25. In a report to Eighth Area Army on 1 August, the Eighteenth Army Commander stated his opinion that the projected Bena Bena-Hagen operations should be treated as secondary to the defense of Lae-Salamaua and the Huon Peninsula area. Finschhafen was to be treated as the most important area. Ibid., pp. 13-8.
26. Although enemy air attacks on the Wewak area were naturally anticipated, the scale and suddenness of the 17 August raid took the Japanese defenses completely by surprise. Defensive precautions were relaxed at the time of the attack. (1) Interrogation of Col. Kazuo Tanikawa, Staff Officer (Operations), Eighth Area Army. (2) Southeast Area Air Operations, op. cit., p. 45.
27. Henceforth the Japanese army air force was obliged to adopt negative strategy and defensive tactics, involving a general retreat to rear-line airfields. Air support of ground operations was severely curtailed, and the schedule of surface transport movement was completely thrown off owing to the impossibility of providing air escort for convoys. (1) Interrogation of Col. Kazuyoshi Obata, Staff Officer (Supply), Eighteenth Army. (2) Southeast Area Operations Record, Part III, op. cit. Vol. II, pp. 249-50.
31. At the time of the Allied landing on 4 September, Japanese forces in the Lae area were commanded by Maj. Gen. Shoge, 41st Infantry Group Commander. Maj. Gen. Shoge had been sent to Lae by Eighteenth Army order to take command of garrison and logistical support elements in the Lae vicinity from 30 July, thus releasing the 51st Division commander to direct the defense of Salamaua. Southeast Area Operations Record, Part III, op. cit. Vol. II, pp. 74-7.
33. Supplies sent to Lae by submarine during July amounted to 150-200 tons, or about one-third of the required amount. In August the volume was increased to 500 tons, but with the Allied landing at Hopoi on 4 September, all supply shipments ceased. Ibid., pp. 150-2.
New Georgia Area (including Kolombangara):
Santa Isabel Island:
The major part of the Army units listed above were drawn from the 6th Division on Bougainville and the 38th Division at Rabaul. The main strength was disposed in the vicinity of Munda, on New Georgia. (Statements by Lt. Col. Shiro Hara, Staff Officer (Operations), Eighth Area Army and Lt. Col. Yoshiharu Kamiya, Staff Officer, Southeast Detachment, and Capt. Ohmae, previously cited.)
36. (1) Southeast Area Operations Record, Part II, op. cit. Vol. II, p. 115. (2) "We had estimated an Allied landing somewhere in the New Georgia group, but did not actually anticipate a landing at Rendova on 30 June. . ." Interrogation of Col. Tanikawa, previously cited.
38. On 4 July the 3d Battalion, 229th Infantry Regiment, was moved from Kolombangara to Munda. This unit, which as the Kenmotsu Battalion, had been virtually annihilated in the Buna campaign, had been reconstituted and refitted in Kolombangara.
40. Despite these difficulties, the Eighth Fleet, by an all-out and costly effort, succeeded in moving several rein forcement groups to the New Georgia area. The total troop strength transported amounted to about five infantry battalions. Ibid., pp. 104-6.
41. An aggressive rear-guard action was fought on Baanga Island by the 3d Battalion, 23d Infantry Regiment, between 11 and 22 August. The battalion then retired to Arundel Island, where it continued to resist the enemy advance until ordered to evacuate in mid-September. Ibid., pp. 131-5.
46. This route, leading over the low saddle of the Markham-Ramu divide, is the natural route of access from the Lae-Salamaua area to Madang. The area in the divide is the largest area free of forest cover on the New Guinea mainland, and is passable for all types of transport throughout the year, with the exception of certain small localities which become boggy during the rainy season. The highest point along this terrain corridor is not more than 900 feet above sea level.
47. Composition of the Nakai Detachment was as follows: 20th Infantry Group headquarters; 78th Infantry Regiment (less elements); 1st Battalion, 26th Field Artillery Regiment; miscellaneous service units. Southeast Area Operations Record, Part III, op. cit. Vol II, pp. 158, 275-6.
50. The native trail from Bogadjim on Astrolabe Bay to Dumpu debouched into the Ramu Valley at a defile which the Japanese designated as Kankirei. In April the 20th Division had begun improvement of the trail into a military road, which was to be extended all the way to Lae. (Cf. Chapter VIII) A prodigious amount of energy was poured into the construction of the road, but by late August the 20-foot wide all-weather surface had only reached a point ten miles north of Dumpu. About 5 September the bulk of the 20th Division troops engaged in the project was diverted to strengthen the defenses of Finschhafen. Intermittent construction continued until 30 September, when the project was finally abandoned. (Statement by Lt. Col. Kengoro Tanaka, previously cited.)
53. (1) Statement by Lt. Col. Nobutake Takayama, Staff Officer (Operations), Imperial General Headquarters, Army Section. (2) The problem of the national defense zone had been under discussion in the Army Section of Imperial General Headquarters for some time. (Statement by Col. Sei Matsutani, Chief, 20th Group (Coordination), Imperial General Headquarters, Army Section.)
60. In addition to these activities the Combined Fleet was watching for a propitious moment to stage a showdown battle with the American Fleet outside the perimeter of the defense line in the Southeast Area. Such an operation was planned, but the opportunity never arose to set the plan in motion. Meanwhile, Japanese naval air strength was slowly whittled down. (Interrogation of Vice Adm. Shigeru Fukudome, Chief of Staff, Combined Fleet.)
65. Elements making up the main body of the 20th Division were: Division headquarters; 79th Infantry Regiment; 26th Field Artillery Regiment (less two battalions); 20th Engineer Regiment; 33d Independent Engineer Regiment; 20th Division special troops. The Nakai Detachment was operating in the Finisterre Mountains under Eighteenth Army control. (Statement by Lt. Col. Kengoro Tanaka, previously cited.)
68. The Navy stationed four submarines off Cape Cretin in order to intercept the enemy reinforcement convoys, but the Allied ships succeeded in running the blockade. Southeast Area Naval Operations, Part II, op. cit., pp. 57-8.
70. The Sugino Boat Unit, composed of the 10th Company (155 men) of the 79th Infantry, carried out counterlandings with four landing barges. This unit, catching the enemy completely by surprise, destroyed three antiaircraft guns, four artillery pieces, ten machine guns, two automatic cannons, twenty automatic rifles, and two ammunition dumps. Four hundred casualties were inflicted on the Allied f orce. Southeast Area Operations Record, Part III, op. cit. Vol. II, p. 175.
73. (1) Ammunition levels of the 20th Division at this time were as follows: Type 94 mountain guns, 135 rounds; Type 41 mountain guns, 78 rounds; Infantry guns, 36 rounds; Mortars, 102 rounds; Demolitions, 436 kilograms. (2) After reaching Satelberg Hill the 20th Division received practically no supplies from rear areas. From 1 October the ration was about 6 shaku (about 1/5 pint) of staple food per day. Southeast Area Operations Record, Part III, op. cit. Vol. II, pp. 185-7, 191-2. (3) "We have been without rations for a month.... We have eaten bananas, stems and roots, bamboo, grass, ferns, and, in fact, everything edible up to the leaves of the trees." Diary of Officer (rank not given) Kobayashi, 80th Infantry Regiment Headquarters. ATIS Current Translations, No. 106, 20 Mar 44. pp. 35-6.
74. The enemy had the following assault shipping at Finschhafen: 6 November, 30 transports; 12 November, 72 transports; 15 November, 3 transports and 22 landing barges. Southeast Area Operations Record, Part III, op. cit. Vol. II, pp. 185-6.
75. On 23 November enemy positions in the vicinity of Jivevaning were bombed by 44 aircraft, and on 26 November, 47 planes hit enemy positions in and around Finschhafen. The 7th Air Division had already returned to Ambon early in November to aid in the establishment of the new national defense line. (1) Ibid., pp. 199-200. (2) Southeast Area Air Operation Record, op. cit., p. 60.
76. The total casualties of the 20th Division were 5,761 or 45 per cent of the total strength. The units hardest hit were the 80th Infantry (59 per cent losses) and the 20th Engineers (66 per cent losses). Southeast Area Operations Record, Part III, op. cit. Vol. II, pp. 219-20.
79. Eighth Area Army also did not regard an enemy landing in the Empress Augusta Bay area as likely. "The first real surprise maneuver after I arrived at Rabaul occurred when the enemy landed on Cape Torokina. . . Because we thought the poor topographical features of this area would hamper enemy landing operations, we did not anticipate a landing. . . and were not adequately prepared." (Interrogation of Lt. Col. Matsuichi Iino, Staff Officer Intelligence, Eighth Army Army.)
Headquarters, Seventeenth Army
Southeast Area Operations Record, Part II, op. cit. Vol. II, pp.160-4.
85. Nanto Homen Sakusen Kiroku Sono Shi Furoku Dai Ichi Seibu Niyuburiten To Dai Jushichi Shidan no Sakusen (Southeast Area Operations Record, Part IV, Supplement No. I: 17th Division Operations in Western New Britain) 1st Demobilization Bureau, Jul 49, pp. 3-14.
97. In late December, owing to the seriousness of the situation, Lt. Gen. Adachi made a trip from Madang to Kiari to direct the dispositions of the 20th and 51st Divisions for the defense of the Sio area. Southeast Area Operations Record, Part III, op. cit. Vol. II, pp. 240-1, 247-8.
99. The usual signs of a forthcoming enemy attack were all present during the latter part of December. Enemy PT boats were active along the coast, and there was a marked acceleration of air activity against Madang and the Saidor area. Ibid., pp. 305-7.
101. Seven infantry companies of the Nakai Detachment remained in the Kankirei area on the Ramu front, under command of the 78th Infantry Regiment commander. Since mid-October the detachment had successfully checked all enemy attempts to penetrate the Ramu Valley line toward Madang. In early December the enemy attempted to flank the Japanese line on the right by sending an Australian infantry battalion to Kesawi, but on 8 December the Nakai Detachment attacked and drove the enemy back to Dumpu. Ibid., pp. 289-96, 343-4, 360-2.
104. General Adachi's plans in early March were as follows: The 41st Division was to station itself in the sector between Madang and Mugil and prepare to attack any enemy landing in the sector east of Hansa. The Nakai Detachment was to be relieved and rejoin the 20th Division. The 20th Division was to recuperate at Hansa and prepare the defenses of that area. The 51st Division, when relieved by the 20th at Hansa, would immediately leave for Wewak to reorganize and defend that area. Southeast Area Operations Record, Part III, op. cit. Vol. III, pp. 6-7.
106. The Hyane (Momote) airfield had been used mainly as a staging field for air units moving to advanced bases in the southeast area. At the time of the Allied landing, there were no operational aircraft on the field. (Statement by Lt. Col. Ohta, previously cited.)
107. In anticipation of new Allied attacks in late February, Imperial General Headquarters had ordered the transfer of five air regiments to New Guinea from the southwest area. These reinforcements had arrived in the theater prior to the enemy landing in the Admiralties, but adverse weather at the time of the landing prevented effective operations against the enemy invasion force. (1) (Statement by Lt. Col. Koji Tanaka, Staff Officer (Air), Imperial General Headquarters, Army Section.) (2) Southeast Area Air Operation, op. cit., pp. 62-7.
108. (1) Southeast Area Operations Record, Part III, op. cit. Vol. III, p. 5. (2) "The taking of the Lae-Salamaua area was the turning point of the New Guinea campaign, but the final step was the taking of the Admiralty Islands. . . . Two large airfields fell to the Allies, and Japanese supply lines (to Rabaul) were cut off. Also from these islands the Allies were able to isolate the individual Japanese positions along the New Guinea coast and to prevent any large-scale withdrawal." Interrogation of Col. Shigeru Sugiyama, Senior Staff Officer, Eighteenth Army.
109. There were no important changes in the order of battle of the forces on Bougainville after the original Allied landing on 1 November. These forces were assembled in February from Erventa on southern Bougainville, Kieta on the east coast, and from the northern tip of the island. Southeast Area Operations, Record, Part II, op. cit. Vol. II, pp. 189-29.
111. Total army and navy forces dispatched to the southeast area from the initial invasion of the Bismarcks up to March 1944 aggregated roughly 300,000. The Army alone supplied 1,800 aircraft and 2,000 pilots. Both the Army and Navy sent the largest consignments of newly manufactured planes to the southeast area. Arms and ammunition enough to equip six combat divisions passed through or were stocked at Rabaul. The Navy lost 50 combat ships and 300,000 tons of transport shipping. (Statements by Col. Kumao Imoto, Staff Officer (Operations), Eighth Area Army; and Capt. Ohmae, Col. Takayama and Lt. Col. Tanaka, previously cited.)
112. Distribution of isolated Eighth Area Army troops was as follows: Rabaul area, 56,512; Bougainville, 31,024; New Ireland, 8,082. Total Army troops, 95,618. In addition there were 12,416 military labor personnel, mostly in the Rabaul area, and about 53,000 naval shore personnel throughout the Army area. Grand total, about 161,000 (1) Southeast Area Operations Record, Part IV, op. cit., pp. 324-5 (2) Statistics complied by 2d Demobilization Bureau, Nov 50.