Chapter 5: The Bougainville Campaign Takes Shape
IN the forthcoming operations in New Guinea the First Army would have more widespread responsibilities than its predecessor, New Guinea Force. From his headquarters at Lae Lieut-General Sturdee controlled four forces deployed in an area that was about 1,000 miles from east to west. Sturdee had not previously held a command in the field in this war. In 1940 he had been appointed to command the 8th Division but after a few weeks had become Chief of the General Staff, an appointment he filled with distinction during the anxious months that followed the entry of the Japanese into the war. In September 1942 he became head of the Australian Military Mission in Washington. His senior staff officer on First Army was Brigadier E. L. Sheehan, who had come to that appointment in 1943 after service on the staff of New Guinea Force and I Corps; his chief administrative officer was Brigadier R. Bierwirth who had held similar appointments on the staff of the 6th Division, Northern Territory Force, and I Corps.1
The big base at Lae was well situated to be the headquarters of an army controlling operations throughout the New Guinea territories. It was about 600 miles from Torokina on Bougainville, 450 from Aitape, and 400 from Jacquinot Bay on New Britain and from Emirau Island, its northernmost area of responsibility. From Lae Sturdee and his staff controlled and maintained not only the four main field formations but a total of 134 formations, units, and detachments, including Angau regions and districts, three Area Commands – Madang, Finschhafen and Wau, seven base sub-areas – at Aitape, Torokina, Madang, Lae, Buna, Port Moresby and Milne Bay, fixed defence units at Moresby and Lae, a multitude of engineer and signals units, and many others. The Army headquarters was much concerned with shipping (the shortage of which was a continual anxiety), liaison with the air force (carried out by fourteen air liaison sections) and movement control.
Lae had now grown into a fairly comfortable town of considerable size. Along wide heavily-metalled roads were lines of buildings with concrete or timber floors, walls only half-height to allow the air to circulate, and ceilings of hessian or tar board. Neatly-painted road signs – Wau Avenue, Finschhafen Avenue and so on – guided the traveller. It was long since enemy aircraft had disturbed Lae’s tranquillity. Twice a week there was an open-air picture show, and often films not yet seen on the mainland were shown. Here as elsewhere, if a tropical storm broke
during the show the audience put on gas capes and went on watching the screen through pouring rain. Five miles away on the banks of the Busu was an officers’ club with room for about 200 to dine, served by well-drilled native waiters, and with a fine floor on which officers danced with nurses to music played by a four-man band.
Sturdee’s principal opponent was General Hitoshi Imamura of the Eighth Area Army whose headquarters were at Rabaul. On New Britain and New Ireland Imamura had the 17th and 38th Divisions and also enough independent brigades and regiments to form two more divisions. The XVII Army on Bougainville, also under Imamura’s command, included the 6th Division, an independent brigade and other units. On Bougainville and New Britain there were also large bodies of naval troops – far larger than the Australian staffs yet knew.
On the mainland of Australian New Guinea, deployed from west of Wewak to the Sepik, was the XVIII Army. Originally it had been part of the Eighth Area Army and later of the Second Area Army, but now was directly under the command of Field Marshal Count Terauchi of the Southern Army, the headquarters which throughout most of the war controlled the Area Armies and Armies employed in the conquest and defence of Japan’s new empire south of China.
The largest formation under Sturdee’s command was II Corps on Bougainville, led by Lieut-General Savige, who, as mentioned, had been Sturdee’s predecessor at the headquarters at Lae until the New Guinea Force staff was renamed II Corps and the First Army assumed control of the whole of Australian New Guinea.
Bougainville is the largest of the Solomon Islands, the chain that forms the north-eastern boundary of the Coral Sea, and, administratively, was part of Australian New Guinea. American troops, having retaken Guadalcanal in 1942, advanced northward along this chain in the next year and on 1st November 1943 their I Marine Corps seized Torokina in Empress Augusta Bay on the western shores of Bougainville. On 15th November the Marines were relieved by the XIV American Corps (Americal and 37th Divisions), which was deployed along an arc about fourteen miles long protecting the airfields at Torokina, with outposts astride the main tracks. The Japanese slowly reorganised and in March 1944 launched a full-scale offensive. It failed, causing them a loss of perhaps 5,000 killed; a total of between 7,000 and 8,000 Japanese were killed and perhaps 16,000 died of sickness during the American occupation.
In late 1944 the Allied base at Torokina was one of several air and naval stations from which intermittent attacks were launched against the isolated Japanese bases in the eastern islands of the New Guinea mandate, principally Buin on Bougainville itself and Rabaul on New Britain. There were also Allied stations at Munda in New Georgia, on the Treasury Islands close to Buin, on the Green Islands north of Bougainville, and on remote Emirau Island north-west of New Ireland. These outer islands had been occupied by New Zealand, American or
Fijian troops and were now garrisoned by the 93rd American Division, a Negro formation. The bases at Manus in the Admiralties and in western New Britain completed the encirclement of Rabaul. Japanese sea and air power in the area was now practically non-existent. The last Japanese air attack on Torokina had been made in March by two aircraft, and no Japanese merchant ship had been seen off the island since January. A post-war Japanese report states that the last transport vessel arrived at Buka from Rabaul on 24th November 1943.
Bougainville Island is about 120 miles in length and about 40 miles in width at the widest part. The mountain chain which forms its backbone rises to a height of 8,500 feet at Mount Balbi, an active volcano. The main wide areas of flat country are in the South-west and the east, and it was there that most of the natives lived and most of the plantations had been established – chiefly round Buin and Kieta. On the western side short, fast-flowing streams, fed by a rainfall that averaged 100 inches a year, drained the mountain chain. These streams were from 10 to 80 yards wide, and subject to floods that rose and fell rapidly. The silt which they washed down, plus the sea sand, formed bars across the mouths and these often made it possible to ford otherwise deep rivers. The bars also caused swamps inland from the river mouths. The Torokina plain, however, had the advantage of being formed of a porous mixture of sand and volcanic ash which quickly absorbed the rain. High forest, with dense undergrowth, covered the island to about the 5,000-feet contour where scantier moss forest began. The temperature on the lowlands was generally hot and humid, although the beaches were pleasantly cool at night.
Off the southern end of Bougainville lie three large islands, Shortland, Fauro and Mono, in the Treasury group, and many smaller ones. At the northern end, separated by a narrow passage, lies Buka, and farther north the Green Islands, a circle of land almost completely enclosing a vast lagoon. Except for the Treasury and Green Islands and the area round Torokina on Bougainville, Bougainville and its neighbouring islands were still in the hands of the Japanese.
As mentioned earlier, the XIV American Corps was to be relieved on Bougainville by II Australian Corps whose main components were the 3rd Division (7th, 15th and 29th Brigades) and the 11th and 23rd Brigades. Major-General W. Bridgeford (3rd Division), Brigadier J. Field (7th Brigade) and staff officers flew to Torokina on 4th September for a reconnaissance and for consultations with the commanders and staff of the XIV American Corps and 37th and Americal Divisions. They spent several days touring the area and discussing problems with the Americans and returned to Lae on the 7th. Soon afterwards Field’s aircraft crashed in rugged country in New Guinea and he and the crew were missing in the bush for about nine days, but made their way home.
The advanced headquarters of the 4th Base Sub-Area, under Brigadier Vowles,2 reached Torokina on 11th September and by the first week in
October the base was ready to receive shipments from Australia. The first American garrisons to be relieved by Australians were those in the outer islands. On 27th September Brigadier A. W. Potts opened the headquarters of the 23rd Brigade on the Green Islands. He placed the 27th Battalion on the Green Islands (where there were still, in December, 6,790 American naval and army men, and 750 New Zealanders – all air force), the 8th on Emirau, and the 7th on Mono with one company at Munda. Thus the brigade freed the 93rd American Division, destined for Morotai.
The 23rd Brigade had been formed in 1940 as part of the 8th Australian Division of the AIF. In the early months of the war against Japan one of its battalions had been lost at Rabaul, another on Ambon, and another on Timor; the headquarters and some of its other units remained at Darwin. The brigade had then been re-formed with militia battalions sent north from Victoria and South Australia. After more than two years of garrison duty in the Northern Territory it had gone to north Queensland and thence to a rear area in New Guinea. Now it had been allotted yet another garrison role.
On 23rd October Sturdee, after visiting the four outer islands, informed Blamey that the 23rd Brigade was merely providing airfield guards and the possibility of Japanese attack was remote. He considered that the garrison work could be taken over in January by the 2/2nd Guard Battalion (a security unit mainly of relatively old soldiers) and/or native troops, making the 23rd Brigade available for Bougainville. Blamey, whose proposal that smaller Australian garrisons should take over in the islands had already been rebuffed by GHQ, replied that the Guard Battalion was distributed among various headquarters and that the native troops were most valuable for reconnaissance. He would consider the matter further.
In making his proposal Sturdee had probably been influenced by Brigadier Potts, a thrustful commander whose career as a leader of troops in the field had been interrupted when he was transferred from the command of the 21st Brigade after setbacks in the Owen Stanleys in 1942. It was natural that Potts should seek a more active part for his force, among whom were still some who had volunteered for foreign service more than four years before. Thus in November Potts, looking for some action, put forward a proposal that his brigade be regrouped and given one or more of four tasks that he outlined:
(a) General reconnaissance of neighbouring enemy territory.
(b) An operation against Choiseul where some 300 Japanese were believed to be at large.
(c) An operation from the Green Islands against northern Bougainville at Buka Passage (it was estimated that there were some 1,300 Japanese in this area),
(d) An operation against Buka Island, on which were some 1,000 Japanese.
Savige would not agree to any of these expeditions. In his weekly letter to Sturdee on 3rd December he wrote:
Potts with 23rd Bde is very restless, and he has all manner of plans to attack and eliminate the Japanese from Choiseul – the Shortlands – to Buka. etc. I have
had to be very definite and firm with him to ensure that he does not embark on any ... adventures, which would undoubtedly land him and me in trouble. I have issued orders to him that he is not to permit any unit, sub-unit, or individual to move from the islands without my authority.
Nevertheless, sympathetically seeking a more active role for the brigade, Savige proposed that “as early as practicable” the 23rd Brigade should be brought to Torokina, leaving only a battalion in the outer islands; but some months were to pass before MacArthur’s headquarters would agree that the garrison of islands where it had formerly deployed a division should so soon be reduced to one battalion, and the 23rd Brigade remained where it was. However, the new posts had spare-time attractions – interesting meetings with Americans and New Zealanders, frequent picture shows, good swimming.
At Torokina Major-General Bridgeford opened the headquarters of the 3rd Australian Division on 6th October. The forces in the area were then still under the command of Major-General Oscar W. Griswold of the XIV American Corps, from whom Lieut-General Savige took over command on 22nd November.3 The only Australian brigade then on Bougainville was the 7th which, in the previous week, had replaced the 129th and 145th American Regiments on the northern side of the perimeter, which elsewhere was still manned by American troops. The speed of the relief depended on the availability of ships, and many ships were then busy supporting the assault on Leyte. The takeover from the American force was completed in three weeks after the arrival of corps headquarters, as follows:
24th November: 2/8th Australian Commando Squadron relieved 164th US Regiment.
23rd–25th November: 9th Australian Battalion relieved II/132nd US Battalion.
4th–10th December: 29th Australian Brigade relieved 182nd US Regiment and I/132nd US Battalion.
11th–12th December: 11th Australian Brigade relieved 148th US Regiment.
Thus the 11th Brigade took over the 37th American Division’s sector, the 3rd Division with two brigades the Americal Division’s. When the relief was complete the 11th Brigade was in the western coastal sector; the 7th was in the northern sector with an outpost in the hills astride the Numa Numa trail; the 2/8th Commando (after a short term on the left wing) in the east with outposts far afield on the tracks leading over the southern slopes of Mount Bagana; and the 29th Brigade on the South-eastern sector with a detached force on the coast north of the Jaba River. The 11th Brigade was directly under corps command, the 7th, 29th and the commando under the 3rd Division, whose third brigade – the 15th, had not yet arrived from Queensland. Thus the main Australian formation – the 3rd Division – faced the main enemy concentrations, which were in the south of the island.
On 9th January XIV Corps, as part of the Sixth Army, landed in Lingayen Gulf on Luzon.
The American air units hitherto in the northern Solomons were replaced by a New Zealand force – No. 1 Group under Group Captain Roberts.3 In November 1944 this was composed of two fighter squadrons armed with Corsairs. By January No. 84 Australian Wing4 (Group Captain Hely5) had been added, and in April the New Zealand squadrons were increased to four.6
The Australian commanders were anxious that their troops should be on their best behaviour in Torokina during the weeks when there would be large numbers both of Americans and Australians within the little perimeter. The Australian was paid less than the American and his canteens were less opulently stocked. He was often a shrewd business man, and the American was often an undiscriminating buyer of souvenirs. A routine order of one of the first Australian units to arrive at Torokina directed that “buying or borrowing of our Allies’ goods be kept to an absolute minimum”, and reminded the men that trading in Government issues was prohibited.
While the Yanks were ready sellers, they were also ready buyers (wrote a unit historian). ... For example, whisky brought £10 a bottle, rum and gin about £7, wine £1.10.0 and beer 10/-. As they were not issued to other ranks, the whisky, rum, gin and wine trade was practically monopolised by officers. Some sold it openly or traded it for cigarette lighters, pens, etc. Some got rid of their issue secretly and others gave the job of disposal to their batmen, who sometimes got a cut.7
An Australian staff officer annoyed officers of one of the first brigades to arrive by telling them that attention should be paid to compliments because the Americans were “exemplary in that regard”; the officers of Australian infantry considered their men also to be well schooled in military etiquette. The incoming troops found the Americans very friendly and helpful. The elaborate base equipment which the Americans were packing up was in contrast to their own more economical gear, American comforts and amenities particularly being on a scale that seemed to the Australian to be lavish.8 The amenities now being provided for Australian troops were, however, on a fairly generous scale. For example, in each brigade was an officer and sergeant of the Army Education Service who conducted a library, moved from unit to unit lecturing on current affairs, supervised correspondence courses and produced news sheets. At the base there were fairly large reference libraries. The army’s monthly magazine Salt and the Current Affairs Bulletin were distributed; and, at Lae, Guinea Gold, which reached a maximum circulation of 57,000, was printed for circulation throughout the forward areas. A broadcasting station was established at Torokina, as at Lae, Aitape and Jacquinot Bay, and wireless receiving sets were distributed. Both static and mobile cinemas gave shows at the bases and in the brigade areas. The Canteens Service was widely established and its efforts were supplemented by those of the Australian Comforts Fund, the Salvation Army and the YMCA.
Far more than the Americans the Australians made themselves relatively comfortable in the front line as well as at the base. In the front line the Americans (to Australian eyes) merely existed, often postponing shaving, washing and comfortable messing until they returned to the showers, laundries and mess huts at the base. The Australians in the front line shaved, bathed and washed their clothing every day if possible. The bush
carpentry and the engineering devices by which they provided themselves in remote places with reticulated water, efficient kitchens, washing places, and all sorts of furniture had become more ingenious as the years passed.
General Savige was now entering his sixth campaign since 1940 – North Africa, Greece, Syria, Wau–Salamaua in 1943, and recently command of New Guinea Force. As mentioned, he took to Torokina the experienced staff that had comprised the headquarters of New Guinea Force until it changed its name and home. His chief staff officer was Brigadier Garrett,9 who had served on his staff in Greece in 1941; his chief administrative officer, Brigadier Pulver,10 had been his brigade major in 1939-40. Savige formed strong loyalties, and in his senior commands in the Pacific brought on to his staff officers who had served under him in the 17th Brigade in Africa, Europe and Asia in 1940 and 1941. His artillery commander was Brigadier Cremor,11 who had led the artillery regiment usually attached to the 17th Brigade in the Middle East fighting.12
Major-General Bridgeford of the 3rd Division had not yet commanded a formation in the field, but was a highly-trained soldier with much senior staff experience in Middle East and New Guinea campaigns. In 1918 he had been a major in a machine-gun battalion in France. When the second world war began he had been at the Imperial Defence College in England, where, in 1940, he formed the 25th Australian Brigade from a medley of troops who had been diverted to England in the crisis that followed the defeat in France. Before this brigade left England Bridgeford was ordered to the Middle East as senior administrative officer of I Corps, and he served as such in the campaigns in Greece and Syria; more recently he had held the corresponding post on the headquarters of New Guinea Force.13
The four militia brigades now arrived or arriving on Bougainville Island had all seen some active service in New Guinea. The first to enter the line – Brigadier Field’s 7th – had fought with distinction at Milne Bay two years before and seen long service in reserve in New Guinea after that; about one-third of the men now in the brigade had been in action at Milne Bay. Lieut-Colonel G. R. Matthews, commanding the 9th Battalion, had
been with the 2/10th in the Middle East; McKinna14 of the 25th with the 2/3rd Pioneer in North Africa; W. R. Dexter of the 61st had been a platoon commander at Bardia in January 1941, and a company commander in the 17th Brigade in hard fighting outside Salamaua in 1943.
The 29th Brigade had served in the Wau–Salamaua operation and in the final phase in the Ramu Valley. Just before embarking at Brisbane for Torokina it had been reinforced by about 1,000 young soldiers whose average age was 20 years and two months – so many that they formed a majority of the men in the rifle platoons. But so thorough had been their training at Canungra that their commander was later to record that they “reacted with almost miraculous quickness to conditions of battle”. Their senior leaders were all men with battle experience in the Middle East. Brigadier R. F. Monaghan, a regular soldier, had commanded battalions in three sectors in 1941 in Syria, and this brigade in the Salamaua operations in 1943. Lieut-Colonel McDonald15 of the 15th Battalion had led a company of the 2/8th in Libya and Greece; J. H. Byrne of the 42nd had served with the 2/31st Battalion in Syria and New Guinea; Coombes16 (to take over the 47th Battalion in January) had led a company of the 2/8th at Tobruk, in Greece and in Crete.
The 11th Brigade, commanded by Brigadier J. R. Stevenson, a learned and enterprising soldier, formerly leader of the 2/3rd Battalion in Syria and the Owen Stanleys, was a Queensland group which had been deployed for the defence of Townsville, Cairns and Cape York Peninsula in 1942; thence, early in 1943, part of it had been sent to Merauke in Dutch territory, forming the remote western flank of the force in New Guinea. There it had patrol encounters with the enemy and learnt to live and move in tropical bush. It left one unit – the 20th Motor Regiment – at Merauke; that unit’s place was taken in the brigade by the 55th/53rd Battalion. The battalion commanders, Lieut-Colonels Abbot,17 Kelly and D. J. H. Lovell, had each served in Middle East campaigns, and Kelly and Lovell in New Guinea in earlier operations.
Of the four brigades the last to arrive – the 15th – was the most experienced. Under Brigadier H. H. Hammer, its galvanic leader, it had probably marched over more of New Guinea than any other Allied formation; it had certainly seen more fighting than any other militia brigade. Hammer did not hide his brigade’s light under a bushel, and it was largely through this hard-worked formation (and the 7th Brigade at Milne Bay) that the people at home began to become aware of the arduous and important roles that militia formations had played. After some sixteen months of campaigning the 15th had spent two months in Victoria, its home State,
and on 13th October (with detachments of the 4th Brigade and others) had marched through Melbourne, 2,200 strong, with seven bands, past a saluting base crowded with eminent political and military people, “Tack” Hammer leading the march. Next day it began moving north again. The senior commanding officer, Lieut-Colonel R. R. Marston of the 57th/60th, had served in this brigade since 1927. Lieut-Colonel A. J. Anderson of the 24th had served with the 2/16th in Syria and the 39th at Kokoda; Lieut-Colonel G. R. Warfe of the 58th/59th had been a conspicuously dashing subaltern in Libya and Greece, and commando leader in New Guinea.
Of the twelve infantry battalions on Bougainville Island in December eight were from Queensland – they were all the militia battalions that State possessed. The policy of sending reinforcements to units without regard to which State they came from had somewhat reduced the territorial character of the force, yet, as a rule, more than half of the men of a unit still belonged to its home State. Thus the burden of the coming campaign was to fall particularly heavily on the Queenslanders.18
When he was allotted his task in August General Savige had asked for three field artillery regiments, one medium regiment and one mountain battery; he was allotted, however, only two field regiments (the 2nd and 4th) and the 2nd Mountain Battery, and his requests for a machine-gun battalion and a Pioneer battalion were not granted. The 2/8th Commando Squadron, one squadron of the 2/4th Armoured Regiment, and a company of the 1st New Guinea Infantry Battalion were given to him. In response to a request for one landing craft company for operational tasks only and with no responsibility for unloading ships, all of which had to be unloaded by barges since there were no wharves, Savige was given the 42nd.
Soon after his arrival Savige compiled a manual of jungle warfare and had it printed on the spot and circulated – an unorthodox step since such manuals were normally produced at army headquarters and not by field commanders.
I realised (he wrote later) that it was essential to obtain some clear pattern of thinking and action for jungle warfare which would be applicable to all units under command. The multiplicity of tasks and shortage of troops denied the use of schools of instruction. I therefore wrote my textbook Tactical and Administrative Doctrine for Jungle Warfare. In accomplishing this task I used Major Travers, who was BM, 15th Bde, in the Salamaua operations, as a sounding board by getting his reactions chapter by chapter.19 It was printed and bound in the field and issued to every officer and NCO. It worked better than we had a right to expect and, at every opportunity, it was referred to in orders and instructions.
There was, however, some criticism of this manual on the ground that it was based too much on experience when fighting over precipitous
mountain trails, whereas much later fighting was on flat coastal country where tanks, mechanical transport and strong concentrations of artillery could be employed.
It has been seen that the first task of II Corps, after freeing the three American divisions employed on Bougainville and the outer islands, was “to gain information which would assist the preparation of a plan for the total reduction of the Japanese troops on Bougainville”.20 At intervals throughout the Japanese occupation of Bougainville parties of the coast-watching organisation, now controlled by the “Allied Intelligence Bureau”, had been behind the Japanese lines collecting and sending back such information. In March 1944 the American commanders decided that they were no longer vitally interested in the enemy’s activities outside the Torokina perimeter, and the AIB parties were withdrawn. With a view to obtaining more recent Intelligence the Australian commanders in September called upon the AIB to resume its work, and intrepid scouts who, with their trusted natives and their wireless sets, had played so important a part in the partial reconquest of the Solomons in 1942 and 1943, were called forward again. Flight Lieutenant Robinson21 was sent to Torokina to insert three parties into enemy territory on Bougainville itself, another into New Hanover and another into Choiseul. Thus Lieutenant Bridge,22 RANVR, was chosen to lead a party into northern Bougainville, Flying Officer Sandford23 a party to operate round Numa Numa, and Lieutenant P. E. Mason, RANVR, a party behind Kieta. Sub-Lieutenant Andresen,24 RANVR, was sent to Choiseul and Sub-Lieutenant Bell25 to New Hanover. By the end of November men had been selected, codes arranged, and parties were ready to set off into the mountains. Bridge, for example, led the veteran Sergeant McPhee,26 Staff-Sergeant B. F. Nash of the American Army, a native sergeant-major, Yauwiga, and twelve other natives. Sandford’s party included Sergeants Wigley27 and McEvoy,28 two outstanding scouts. These parties and the native police led by officers of Angau were for a time to prove the main source of information about the enemy.
The Intelligence staff of XIV American Corps had estimated the strength of the Japanese forces on Bougainville at 12,000, some 5,000 of these being in base units. These, they believed, were all that remained of the XVII Japanese Army commanded by Lieut-General Hyakutake, whose headquarters were in the Buin–Faisi area; the XVII Army included the 6th Division, the 38th Independent Brigade, and other smaller formations.
In October, because Australian forces were going to Bougainville, the Intelligence staff at LHQ began to take a close interest in the strength of the Japanese there, and on 11th October produced an estimate of 25,000 – more than twice the figure stated by GHQ This difference of opinion, one of a series that had occurred between the Australian Intelligence staff and Major-General Charles A. Willoughby, the head of the American Intelligence staff, led to some sharp exchanges. The Australian estimate had been largely based on a report of the XVII Japanese Army for March 1944 captured in the Marshall Islands in July, giving the ration strength on Bougainville in late March as 41,200.
On 20th October Willoughby wrote to the Australian Director of Military Intelligence, Brigadier J. D. Rogers, in protest.
Several discrepancies (he wrote) are readily noted in the figures.
(a) Under Front Line Strengths it will be noted that total enemy dead in the Torokina operations would amount to 2,651, whereas in excess of 3,000 bodies were actually buried by American troops following the attack.
(b) Note also that strength in the L of C Areas increased from the time the attack was begun up to late March (after the battle) when in actual fact a full-scale withdrawal from the area is known to have occurred.
(c) The same point is illustrated by taking the numbers reported in the area; a total of 23,102 at the time the 2nd attack was begun as opposed to 21,515 following the operation. The difference here would be 1,587, a ridiculous figure considering the casualties suffered and the withdrawal following the attack.
(d) Note that the document specifically says that natives employed as carriers are also listed. There is no reliable basis for estimating or even guessing at the number so employed, i.e. ration reports are not equivalent to strength reports.
(e) Lastly, note that in the total strength column, taking the figure from early December (which includes natives) 44,000 and the strength reported in late March 41,200, would admit total casualties of only 2,800 during the entire four month period. In no case do casualties figured from the document coincide; nor do they even approach known enemy dead ... as has often been the case with Japanese official reports, the particular writer is more concerned in impressing Imperial Headquarters with his “valorous deeds” than accuracy. ...
(f) Ration strengths have proved notoriously unreliable in the past and this Section sees no reason to suddenly accept them as accurate now. ... Our present strength estimate [is] considered adequate.
Further support for this contention is available in recent PW reports from the area particularly ... a sergeant who ... reports a battalion with strength of 119 men, several companies averaging, even after reorganisation, about 100 men each with some as low as 40 and remnants of entire units disbanded to provide men
for the companies. Such figures do not support a strength estimate of 25,000. ...
For the past two years an unwritten practical agreement has been in effect by which any discrepancies in strength estimate between LHQ and GHQ has been settled by inter-camera discussion between the two Order of Battle Sections. In
view of this, and in view of the fact that this Section represents the opinion of GHQ, SWPA, the sudden dissemination of this increased strength for Bougainville is suggesting publicly an open discrepancy which is undesirable.
Furthermore, the subject involved is a clear-cut departure, without warning, from a previously most satisfactory process, i.e.
(a) Joint meeting to determine Order of Battle.
(b) Joint agreement on basic totals.
(c) Joint definition of estimates.
This arrangement was faithfully observed in the past; it was found that discrepancies were generally noted in Washington and London and explanations requested; it was simple to adjust locally. Finally, LHQ Intelligence has no source of information beyond that of GHQ Intelligence; they feed out of the same trough.
For professional solidarity, I suggest that this matter be discreetly adjusted in later editions.
Rogers then wrote a memorandum pointing out that the Australian Intelligence Review had on several occasions published estimates at variance with those of Willoughby’s staff and quoted five instances in each of which an Australian estimate had varied greatly from GHQ’s and had been proved more nearly correct. One example was the estimate of the enemy strength at Finschhafen before the Australian attack. The GHQ estimate was 300 to 400, he wrote, the Australian 6,000,29 which proved an underestimate. “In each of these cases we took the stand after negotiations had failed,” wrote Rogers, “in order not to deceive the Commander of our own forces.” On 13th November, however, Blamey directed that for publication throughout the Intelligence network the GHQ estimate must be accepted as the official estimate, but where Rogers’ staff produced a differing estimate he should inform Blamey.
The problem was further discussed between the staffs at GHQ and LHQ and in mid-December both agreed to accept an estimate of 17,500 “effectives”.
The various revisions of this estimate will be recorded later, but probably the reader would prefer at this stage to disperse the fog of war and find out how many Japanese were in fact on Bougainville in October 1944. The true total was somewhere between 37,000 and 40,000, including civilian workers who could be and were incorporated in the military or naval forces; 23,500 Japanese would surrender in August 1945. The exact strength of the Japanese force on Bougainville at other times and its exact casualties will probably never be known – the Japanese burnt many documents, though evidently not so many as they pretended. Two careful studies of the problem were made after the surrender, one being completed by Lieut-Colonel Wilson,30 the senior Intelligence officer of II Corps, in October 1945, and the other by Captain Campbell31 of the 23rd Brigade in February 1946, after further interrogation of Japanese officers. Campbell’s figures are higher than Wilson’s in several places. Campbell found that there were 65,000 Japanese on Bougainville when
the Americans landed, the deaths in battle during the American period were 8,200 and the deaths from illness 16,600. Of about 40,000 remaining when the Australians took over, 8,500 were killed in battle or died of wounds and 9,800 died of illness. (Wilson, in the earlier study, had decided that deaths in battle in the American period had been 7,000 and in the Australian period 6,800.32)
Colonel Hattori in The Complete History of the Greater East Asia War, published in 1953, says that 52,000 Japanese remained on Bougainville after the counter-attack against the Americans. Thus if deaths in battle in the American period had been 8,200 the original garrison must have been something over 60,200; if they were 7,000 it must have been something over 59,000. It seems certain that for some months after the big counter-attack Japanese were dying of illness at the rate of about 3,000 a month. Indeed the neglect by the Japanese officers of their own men seems to have been little less callous than their neglect of their prisoners of war.
The Intelligence staff of XIV American Corps had decided that by July or August the enemy had consumed all significant quantities of army rations, and that their morale was low chiefly because of shortage of food and medical supplies but also because of lack of weapons and loss of faith in the high command. The Australian Intelligence staffs largely rejected these conclusions. Documents were captured which showed that in April the Japanese had possessed 750 tons of food, and in the next four months had received about 250 tons from submarines. This food was issued only to troops in contact with the enemy, even though, during July, August and September, about 3,000 Japanese had died, partly of malnutrition, in rear areas. It was decided that a substantial part of this 1,000 tons of food was intact and additional quantities were arriving by submarine and – more important – that by November 1944 a well-planned program of agriculture was providing enough food to sustain all troops on the island.
The Australians had now reached the conclusion that the Japanese had disbanded depleted units to reinforce others and were maintaining a well-disciplined and efficient force. They decided that, at the end of November, the force included the 38th Independent Mixed Brigade, built round the 81st Regiment, and the 6th Division with three depleted infantry regiments – 13th, 23rd and 45th. Of these the 38th Brigade was believed to be chiefly concentrated at Numa Numa, with part of the 81st Regiment forward on the trail; most of the 13th Regiment was believed to be round the Jaba River–Gazelle Harbour area, with the 23rd farther south, and the 45th round Kieta on the east coast. (All this was later found to be correct.)
The American corps had built some fifty miles of good roads within the perimeter. The Australian commander decided to maintain only about
half of the roads in this base area and concentrate his resources on improving and extending the jeep tracks leading forward. It was found that notable economies could be achieved. For example, along the coast between the little Torokina plain and Kuraio the mountains fall steeply towards the sea, and the first natural approach to the mountain mass east of the coastal ledge was along the Laruma River gorge into the tributary Doiabi gorge and thence up the face of a steep escarpment. The twelve-mile road which the Americans had built along this narrow cleft crossed the rivers twenty-six times over boulder-strewn fords. At the head of the ravine artillery was emplaced ready to fire at unseen targets about three miles away but 2,000 feet above. From the top of the escarpment a track set off across the mountains to Numa Numa. When the Australians arrived the fords were in poor condition; at each a tractor was stationed to haul trucks through the stream and the journey took four hours and a half. By improving the fords the need for tractors was removed and the journey could be made in an hour and a half.
The gun positions in the Doiabi gorge had unusual features. The guns had to be manhandled part-way up the steep slopes on one side of the gully and there placed on platforms. The angle to the crest on the other side of the gully over which the guns had to fire was about 27 degrees. The guns could not have been used effectively without the special incremental charges developed in the war for use in rugged terrain. The incremental charges also had the advantage of giving the shells a steep angle of descent which was important in engaging close targets in hilly country.
In the Japanese-held territory there were native tracks along the coastal plain some of which had been improved sufficiently to carry light vehicles. From Mawaraka southward, for example, the track had been widened to about 12 feet. In the interior a network of footpaths linked the mountain villages, and two main tracks crossed the island over saddles in the mountain chain. One was the Numa Numa trail, mentioned above, connecting Torokina and the east coast, and the other connected the Jaba River with Kieta.
From the outset of the II Corps’ operations lack of shipping and particularly of barges (largely a consequence of the lack of ships to bring them forward) was a major handicap. Not only were there not enough barges to make large-scale landings possible but not enough even to carry adequate supplies to forces along the coast and in the outer islands. In the 42nd Landing Craft Company there were in December only 12 craft and even in February only 29,33 although the establishment was more than 60. The small ships available to II Corps were manned by the 13th Small Ships Company, which, with the 42nd Landing Craft Company, formed
the 1st Water Transport Group (Lieut-Colonel Chesterman34). The small ships eventually included four 300-ton wooden ships, six 300-ton lighters, and four 66-foot trawlers. The shortage of larger ships to bring in supplies and equipment from Australia was acute. The Australian Government had placed practically all its ships in the Allied pool and the best of them were supporting the operations farther north. At Christmas 1944 II Corps held only three days’ reserve rations – apart from those held by the units, which had supplies for up to fourteen days.
Army leaders considered that the American staffs were able to spare enough Australian shipping to ensure the adequate supply of the force on Bougainville, but that the Australian Ministers would not “stand up to the Americans” in this matter. Early in February a diarist on Bougainville wrote:
Here is being conducted one of the largest single operations the Australian Army has undertaken. One division and a half are engaged, with considerable artillery and some tanks. However, so slender is the supply of shipping that even rations were recently disturbingly low; the outer islands are just managing on supplies provided by an old wooden steamer; the one landing craft company has only one-half of its complement of craft, there is not even a moderate-sized antisubmarine vessel in the area. Yet for more than a year, when there was barely contact with the Japanese force on the island, there were 50,000 troops here, much shipping, large air forces, a lavishly-equipped base.
The leaders in Australia were trying hard, however, to get craft forward to this and other areas. Army Headquarters appealed to the War Office on 11th January 1945 for a ship able to transport from Cairns to Lae, Torokina and New Britain 130 small craft urgently needed there and ready to go. In addition some 27 new craft were being produced each month. The War Office could not help immediately but discovered that the Royal Navy might be able to provide a “heavy lift ship” by the end of March.
General Blamey signalled to General Berryman at GHQ to press firstly for an LSD (Landing Ship, Dock) or alternatively two Liberty ships until movement of these craft had been effected. GHQ replied that all they could do was to load the craft on the decks of the four American ships assigned to take supplies to the Australian forces during February. This method had in recent months resulted in the moving of about 11 craft a month and might move 30 a month in February and March.
Blamey on 10th February asked that the Prime Minister should ask GHQ for the loan of an LSD and he did so on 28th February. Time passed. On 26th March no reply had been received to Mr Curtin’s request to GHQ. Nine of the 130 craft had been shipped to New Guinea, 23 were moving forward under their own power, and it was decided that 47 more would be sent off under their own power; these ranged from 125-foot wooden cargo vessels to ALC40s (Australian Landing Craft, 66 feet in length and weighing 35 tons). The appeal to GHQ failed to produce
results. By 30th June 171 craft had been moved forward, largely under their own power.
The Americans had been employing only some 675 native labourers on Bougainville. An additional 500 were allotted to II Corps in October, and in November Savige informed the headquarters of the First Army that by March he would need a total of 1,600 for operational work, and in addition the Base Sub-Area needed 1,300. As operations proceeded and lines of communication lengthened this estimate was found to be too low. By the end of March the 1,500 employed by II Corps were reckoned too few and First Army was informed that 2,000 were needed (apart from the requirements of the base). This figure was reached by recruiting natives locally.
It will be recalled that front-line responsibility was first taken over by Australians on the left of the perimeter. There the Americans had been sending a patrol each week towards Kuraio Mission some 20 miles north along the coast from Torokina. On 6th November Major N. I. Winning’s 2/8th Commando Squadron took over this role and made these patrols regularly for the next five weeks, but met the enemy only once – on 9th December, when Lieutenant Astill35 and five men came upon two unarmed Japanese near Amun, far beyond Kuraio, demanded surrender and, when the Japanese refused, shot them.
The patrols moved part of the way along the coast in barges. They found their maps of the area beyond the perimeter “inaccurate in all respects” – a complaint later to be heard from each sector in turn. Early in December a patrol met at Kuraio three Indian prisoners who had escaped from a Japanese camp in north-east Bougainville. On 12th December the 2/8th Commando handed over this area to the 11th Brigade.36
When the road along the Laruma–Doiabi gorge in the central sector reached the escarpment one track branched westward towards a cluster of villages called Sisivie, while the Numa Numa trail proper led east through Piaterapaia which was some four miles beyond the escarpment. On a knoll named George,37 beyond Piaterapaia, had been established an American outpost; on Little George, about 50 yards beyond, was a Japanese outpost. Each was in view of the other but a kind of informal truce had long existed.
From 23rd to 26th November the 9th Battalion, with the 12th Field Battery and other detachments under command, took over this sector.
Its supplies were carried by truck up the Laruma River gorge and then manhandled 1,500 feet up the escarpment to the Numa Numa trail.
After almost two years (wrote the 9th Battalion’s diarist) the battalion had the honour bestowed on them to face the enemy again. ... This battalion along with its neighbouring battalions in 7th Brigade were the first Australian troops to retard the advance of the Japanese on Milne Bay in August 1942. ... The troops are eager and keen to meet the enemy and make full use of their years of training.
The 9th Battalion’s first task was actively to reconnoitre the Sisivie area with a view to attacking it later; and to secure ground from which such an attack could be launched. It had been believed that the main supply route from Numa Numa passed through Sisivie, but captured documents and interrogation of prisoners revealed that Sisivie was merely an outpost and that the Piaterapaia area was the terminus of the enemy’s line of communication; consequently the battalion’s efforts were concentrated in that direction. At 1.50 p.m. on the 24th one rifle shot was fired from Little George into the battalion’s area – the first shot in the Australian operations on Bougainville.
George was a steep-sided knoll only twelve feet wide from crest to crest; on it the forward company occupied an elongated position some
250 yards in length forming a deep salient between Mount Deacon on the east and Bawabu Ridge on the west. Little George was even smaller. Beyond lay a larger feature – Arty Hill, so called because it had been often shelled by artillery and laid bare.
On the 25th a small patrol moved stealthily to the rear of Little George and was fired on, two men being wounded. On the morning of the 29th the battery in the Doiabi Valley fired high-explosive and smoke shells on to Arty Hill, mortars fired smoke bombs on to Little George, and into the smoke a single platoon attacked. At the run the men reached the top of Little George before the Japanese emerged from shelter, opened fire with machine-guns and threw grenades. The attackers did not falter but worked their way forward in pairs, one man firing on a post while the other moved close and threw in grenades. Lieutenant Deacon,38 the commander, was wounded but carried on. In about half an hour the position was gained. Two Australians had been killed39 and six wounded, of whom three remained on duty. Twenty Japanese dead lay on the hill, including a lieutenant and a sergeant. The expected enemy counter-attack was made in the evening by about 40 Japanese. It was a frontal thrust and gained no ground. Until dawn the enemy tried in vain to infiltrate. continued.
In the next few days patrolling continued. Brigadier Field suggested to Colonel Matthews that he should occupy Sisivie. On 3rd December Lieutenant Mole40 and his platoon advanced. As they neared the Japanese posts Mole and three men crawled forward. There was a burst of fire which killed the leading man, Private Abbott,41 and wounded the others. Mole, though mortally wounded, crawled forward to Abbott, found that he was dead, and ordered the whole platoon to withdraw.
Next day it appeared that the enemy was responding to the Australian thrusts by launching a full-scale encircling attack from heights east and west of the trail – Mount Deacon on the east and Bawabu Ridge on the west. A company of the 61st Battalion was placed to defend the junction of the Doiabi and Asaba Rivers and the heights were shelled; patrols later found that the enemy had abandoned them. Next day the 9th Battalion began moving forward on Bawabu Ridge towards Pearl Ridge42 which dominated the area to the north and along which it was now evident that the enemy’s line of communication ran. On the 13th ten aircraft attacked the enemy’s positions for half an hour with naval depth-charges and the artillery shelled them. Under cover of the bombardment a patrol of ten men went forward to Arty Hill to observe, were fired on and lost one man killed and two wounded.
Matthews now planned an attack on Arty Hill by a full company. At 7 a.m. on 18th December Major Blanch’s43 company formed up on the sheltered side of George and Little George, on top of which men of a supporting company were walking about nonchalantly to mislead the enemy into thinking that it was to be another uneventful day. Twelve New Zealand Corsairs attacked the Japanese positions; the battery of the 4th Field Regiment opened fire from its positions in the Laruma River Valley; medium machine-guns fired from Mount Deacon and Bawabu Ridge – that is, from each flank – on to the reverse slope of Arty Hill at ranges up to 1,000 yards. After thirteen minutes of bombardment, the attackers advanced through the smoke along the razor-back ridge which was the only means of approach to the bare hill. Months of intermittent shelling had destroyed the bush and so loosened the soil on the steep slopes that the men had difficulty in scrambling up them. By 8.10 the leading troops were near the crest of Banyan Knoll and were meeting sharp
small arms fire from Japanese in covered weapon-pits. Grenades were hurled down on them.
They pressed on. Sergeant Allan,44 commanding the right platoon, led the way to the top of Banyan Knoll, shot a Japanese machine-gunner and himself fell dead. His men carried on up the slopes of Arty Hill. As at Little George, the attackers worked in pairs, one man covering an enemy post with fire while the other attacked from a flank with grenades. After more than an hour of close fighting the position was won and the defenders were digging in and setting up wire in preparation for the probable counter-attack. There was none: a prisoner said that there were not enough men left to attack. Five Australians were killed and 12 wounded of whom 4 remained on duty. Twenty-five Japanese dead were counted, 2 Japanese were taken prisoner, and from 10 to 20 recently-buried bodies were found.45
On the 20th the 25th Battalion began to relieve the 9th, which had then been in the line for a month, and was given the task of gaining information in preparation for an attack on the next feature, Pearl Ridge. On the 22nd, after an ineffective air attack, one platoon of the 25th made a probing thrust towards Pearl Ridge from Barton’s Knoll, losing one man killed and three wounded. It was estimated that from 80 to 90 Japanese were entrenched on Pearl. Next day a patrol was ambushed beyond Arty Hill and its leader, Lieutenant Smith,46 was killed.
While these operations were in progress on the Numa Numa trail, the 2/8th Commando, next on the right, had taken over responsibility for the tangled mountain area rising to an altitude of 4,000 feet south and South-east of Mount Bagana, and known as the Hanemo sector. When the commando squadron took over from a company of the 164th American Regiment there had been no contact with the enemy for several weeks, and it was believed that only a handful of Japanese were in the neighbourhood. For five weeks from 24th November, when the relief was completed, a commando troop patrolled but met Japanese only twice, killing two and capturing another. By 27th December, when the 61st Battalion relieved the troop, it was considered that the area was clear and the flank of a force advancing down the coast would be safe.
From the outset, it had been recognised that the southern sector was the principal one, since beyond it lay the main Japanese base, and Savige
had decided to concentrate the 3rd Division in the west and south for that reason, pitting it against the 6th Japanese Division. On 2nd December General Bridgeford informed his senior officers that the first phase of the operation would be the capture of Mosigetta and Mawaraka, to be used
as bases for further advances, but before this operation could be undertaken complete information about the enemy’s dispositions was needed. The task of obtaining this information was given to the 29th Brigade Group, in which was included the 2nd Field Regiment and other units. Brigadier Monaghan was instructed not to employ more than one battalion in an attack without the approval of the corps commander. By 10th December the brigade had completed the relief of the 182nd American Regiment.
The southern sector was served by a narrow track near the beach which, between Torokina and the Jaba, crossed a number of streams subject
to sudden flooding after heavy rain. When the American regiment was relieved it was maintaining an outpost just north of the mouth of the Jaba, the Japanese an outpost just south of it.
When Monaghan took command he ordered Captain Johnson’s47 company of the 1st New Guinea Battalion stealthily to reconnoitre the bush between the Mariropa and Jaba Rivers. There they met only one Japanese. From the 13th onwards the New Guinea patrols, having crossed the Jaba, explored the country along the south bank, where, on the 16th, they captured a Japanese medical officer (who provided useful information) and surprised and killed four other Japanese. Next day a company of the 15th Battalion crossed the river and established itself. On the 18th (the day of the capture of Arty Hill) a second company of the 15th Battalion landed from barges on the beach well south of the Jaba and later a third company crossed the river. The last two companies were commanded by Major D. Provan and formed a group directly under Monaghan’s command.
Next day the 15th Battalion attacked a Japanese post near the river mouth and drove its occupants into an ambush set by the New Guinea Infantry on the road to Kupon. Nine Japanese were killed and the remainder – perhaps ten – fled into the bush. Meanwhile Provan’s patrols, advancing without opposition, established a base more than a mile beyond the Tuju River. By the 21st there was evidence that the enemy in response to this rapid move deep into his territory was bringing forward reinforcements, and Monaghan obtained permission to send an additional company (from the 47th Battalion) across the Jaba to join the 15th.
A strong Japanese position flanked by swamps was encountered on the track leading along the south bank of the Jaba on 23rd December and a patrol of New Guinea troops was sent to take it in the rear. From this day onwards the infantry received impressive support from the 2nd Field Regiment. Next day the native soldiers took three prisoners who said that 200 Japanese had left Mosina on the 22nd to launch a counterattack. This attack did not develop. By the 26th patrols had cleared the area south of the Jaba and a platoon of native troops had surprised a strong Japanese patrol and killed eighteen out of perhaps twenty-five. Captured papers and the interrogation of prisoners seemed to indicate that there were one or two battalions of the 13th Japanese Regiment round Mosina.
Thus by the fourth week of December the tacit truce on Bougainville had been broken. There had been sharp fighting on two of the three main sectors, more than 100 Japanese had been killed, their forward posts in each area had been captured, and they were bringing up reinforcements. On the 23rd the aggressive policy that Bridgeford had adopted (subject to the approval of higher authority) received approval. That day Savige
issued a crucial instruction: in effect, that he intended to open an offensive. Two of its paragraphs read:
8. 3 Aust Div
To destroy Japanese forces in Southern Bougainville.
(a) To conduct operations to clear the enemy from, and to establish control of, the area south from the Jaba River to the Puriata River.
(b) To push forward patrols south of the Puriata River to gain information of and establish contact with Japanese main areas of concentration, in preparation for the next southward move.
(c) To secure and control tracks leading from the east coast on the flank of the line of advance.
(d) To construct necessary tracks in the area of operations to give freedom of movement inland from the coast and parallel to the coast if necessary.
(e) Employment of Forces
In carrying out the immediate role, a force exceeding one infantry battalion will not be committed to an attack role without prior approval of 2 Aust Corps.
9. 11 Aust Inf Bde Gp
(a) To prevent enemy penetration into the Laruma River Valley from the direction of Numa Numa.
(b) To secure the feature known as Pearl Ridge and establish on it firm bases from which to operate patrols towards Numa Numa.
(c) To make no advance beyond Pearl Ridge except by reconnaissance and fighting patrols.
(d) To establish in the Cape Moltke area a firm base for one infantry company and to patrol from there with the object of establishing control in the area Kavrata–Cape Moltke–Amun.
(e) To maintain regular patrols from the perimeter to a minimum depth of 4,000 yards on all lines of approach within the Brigade sector.
“Thus the campaign to destroy the Japanese on Bougainville became resolved into three simultaneous offensives. The ultimate aim in the north was to force the enemy garrison into the narrow Bonis Peninsula and there destroy it. In the central sector the offensive was to clear the enemy from the high ground near Pearl Ridge and then by aggressive patrolling to threaten the important enemy line of communication along the east coast. The main enemy concentration was in the garden area in southern Bougainville and here the decisive battle of the campaign must eventually be fought.”48
The Allied Intelligence estimates of the whereabouts of the main Japanese formations on Bougainville proved accurate. The main shortcoming was that the strength of the naval troops was underestimated. At the time of the arrival of the Australians there were about 11,000 naval men, including 3,500 civilian workers, on the island; the 87th Garrison Force, about 4,000 strong, was in the Buka area, and in the south were two strong forces of marines – the 6th Sasebo Special Naval Landing Force (about 2,000) and the 7th Kure Special Naval Landing Force (about 1,500). Indeed the naval forces were about as strong in fighting men as the 6th Division.
During the latter half of 1944 approximately 35 per cent of the Japanese force was on gardening and fishing duty, 15 per cent on transport duty, 30 per cent sick,
and only 20 per cent in the forward areas. The gardens grew sweet potatoes, corn, egg fruit, beans, peanuts and green vegetables. Pawpaws, bananas, coconuts and pineapples were plentiful. There were chickens in every unit’s lines.
The policy of concentrating on food production had been made the easier by the fact that it became evident that the Americans did not intend to extend the area that they occupied. General Imamura, at Rabaul, General Hyakutake’s senior, favoured a “live and let live” policy. The Japanese believed that they would eventually be reinforced and open a new offensive.
The Japanese first learnt that Australians were arriving on Bougainville from a native who had been at Torokina. The news was confirmed in a broadcast by General MacArthur. Opinions were divided concerning the significance of the change, but, in case it was to lead to an offensive, commanders in the field were ordered to meet all patrols with aggressive action. Hyakutake issued an appreciation in which he stated that the courses open to his enemy if he attacked were (a) to land in Gazelle Harbour and at the same time push south across the Jaba, (b) to land at Numa Numa and try to cut the north-south line of communication, or (c) to land on the south coast between the Hari River and Kaukauai and strike at the main base. The force in the Emperor Range was reinforced from the 38th Brigade, 3,000 strong, at Numa Numa and the headquarters of the 81st Regiment moved into the area; the 6th Division established an advanced headquarters at Mosigetta to control the defence of the Jaba River and Gazelle Harbour. It was considered that the new troops would not be able to attack before the middle of January.
The successful attack on Little George by the 9th Battalion on 29th November, six weeks before it was expected, surprised the enemy commanders and convinced them that the Australians were determined to open an offensive. Reinforcements numbering 450 were hurried into the central area (there were 2,000 troops deployed in or forward of Numa Numa) and Colonel Atsushi Kaneko of the 81st Regiment took command. A further 1,000 troops were sent from Kieta and the north to Numa Numa. Hyakutake was convinced that the attack on the Numa Numa trail would be accompanied by a landing at its eastern end with the object of severing his force. The quantity of artillery used in the attack on Little George and later Arty Hill convinced the Japanese that a determined thrust was being made. Arty Hill was defended by men of the 5th and 11th Companies of the 81st Regiment.
Meanwhile the 13th Regiment was attacked on the Jaba River. Lieut-General Kanda of the 6th Division did not propose to contest the south bank of the river, considering that the crossing was merely a feint and the principal offensive would be made by sea; the main body of the defending force-1,500 men – was retained in the Mosigetta area. By January Kanda estimated that one Australian division, its name yet unknown, was south of the Jaba, with 25 guns.
Although the Australians had thus worked out the dispositions of the principal Japanese military units with some precision, the Japanese had gained little knowledge of their enemy’s order of battle and his dispositions. Not even the titles of the major formations were known to them until they were told much later in a broadcast from Australia that troops of the 3rd and 11th Australian Divisions were on Bougainville. The Japanese Intelligence staffs were weak in numbers and training. On Bougainville no Intelligence reports were issued, and, after the surrender, officers were “amazed at the extent of the knowledge the Australians possessed of Japanese units, movements and personalities ... no system existed in XVII Army to produce such results”.49 Their booklet on the Australian
Army contained only pre-war information. It seems that throughout the war the Japanese acquired little information about the Order of Battle of the Australian home army beyond what they had probably copied from pre-war publications. Until well into 1942 the Australian Army had continued in a carefree fashion to publish in the telephone directories what amounted to a detailed Order of Battle of the home forces, but the Japanese appear to have missed even that opportunity of bringing their information up to date during 1940 and 1941.