THE BATTLE OF BOUGAINVILLE

The American forces which landed at Torokina, in Empress Augusta Bay, on 1 November 1943 established a shallow beachhead inside which three airstrips were constructed. This provided air bases only 200 miles from Rabaul which at that time was the principal Japanese base in the South-west Pacific area. Relieving troops pushed out the perimeter a little more, and at certain points outposts were manned beyond the boundaries to deny vital ground to the Japanese. The island had not been an objective in itself; it was merely a stepping stone for the northward advance of the Allies. The American operational role was therefore strictly limited. After the crushing repulses of two large-scale counterattacks the Japanese commander withdrew his forces and concentrated them in three main areas--Buka Passage in the north, Numa Numa and Kieta in the east, and the Buin-Mosigetta plains in the south.

The two American divisions were gradually withdrawn for operations in the Philippines; and by the time the first of them--the 37th --had quit Bougainville the Australian campaign was under way.

When the Australians, under Lt General S G Savige, Commander of the II Corps, assumed responsibility in November/December 1944, the main Japanese force was known to be concentrated in the south. From there the Japanese 17th Army Group controlled all Japanese forces on Bougainville and the outer islands.

With the relief of the Americans the campaign developed into three separate drives, controlled and co-ordinated by II Corps. In the north it was planned that the Japanese should be forced into the narrow Bonis Peninsula and contained there. In the centre the seizure of Pearl Ridge would give command of the east-west trails and protection against any repetition of the vicious counter-attacks launched against the Americans in March 1944. At the same time it would open the way for a future drive to the east coast. The decisive battle, however, would occur in the south where the bulk of the Japanese force was located.

Under the command of General Savige were five Australian infantry brigades--the 7th, 15th and 29th (comprising the 3rd Division) and the 11th and 23rd, the last named brigade being disposed as garrison troops on the islands of Emirau, Green and Treasury and at Munda in New Georgia. The 3rd Division was commanded by Major-General W Bridgeford. Air support came from the American First Marine Air Wing, the RAAF and the RNZAF.

The first operational role undertaken by the Australians fell to the 2/8th Cavalry Commando Squadron which, took over the routine weekly patrol to Cape Moltke on 7 November 1944. On 23 November, the 9th Battalion (7th Brigade) took over from the Americans in the Doiabie area, some eight to eleven miles inland along the Numa Numa trail. This placed the Australian troops in typical ridge country. The role of the battalion was to exert continual pressure on the Japanese and to make local advances towards Pearl Ridge, the commanding high ground in the area. Possession of this feature, with a force at Sisivie on the left flank, would give the Australians control of the only inland approach to Torokina.

The Australian force at Sisivie remained static except for the usual patrolling. The advance to Pearl Ridge stemmed from the important Piaterapaia Ridge which rose out of the Doiabie River valley. This was the logical point for any forward movement as along it ran part of the Numa Numa trail leading from Torokina to the Japanese base at Numa Numa on the east coast. It was on Piaterapaia that the 9th Battalion struck the first blow of the Australian campaign. On 29 November a platoon of D Company moved across the fifty yards between their position on George Hill to attack the Japanese on the next knoll, Little George. In an hour's sharp fighting they took the position.

This success was followed by another on 18 December when C Company of the battalion, in a company attack, stormed the important Artillery Ridge--the next high feature before Pearl Ridge. The Japanese were present in considerable strength. The once dense tree and secondary growth had been blasted away over a long period by the concentrated fire of American 155 mm. guns back in the Laruma River valley. With the binding vegetation gone, the shelling started landslides which made the already precarious slopes more difficult to traverse.

The only line of approach was along a single track on either side of which the ridge fell sheer away. The start line, where the ridge splayed out, was reached without opposition owing to the effective neutralising fire of the artillery, mortars, and medium machine guns. As the ascent proceeded, the support lifted. The loose soil on the slopes gave scant foothold on the flanks and the attackers floundered and scrambled, rather than climbed. Three Vickers on neighbouring ridges kept firing until the last minute.

With the Australians only ten yards away the Japanese jumped from their pillboxes to man open weapon pits running along the entire rim of the knoll. Because of the steepness of the slope the attacking force could not bring fire to bear; north of could the Japanese to any extent, without exposing themselves. The action quickly developed into a grenade battle. A hail of grenades rained down as the two platoons clambered to the summit. The attackers worked in twos and threes, with Owen guns and grenades. Selecting a weapon pit the Owen gunners heaved themselves over the rim and poured in fire while The other man moved in and threw grenades. It was intense, bitter fighting. The new phosphorus grenades were used, their smoke blanketing the pillboxes while the infantry closed in for the kill. After nearly an hour's fighting the position was Australians. Japanese killed during the attack numbered thirty-five; and about twenty unburied and partly buried bodies were found. Australian losses were five killed and ten wounded.

In the southern sector it was planned to make an early advance from Australian forward positions at the Jaba River against the main Japanese concentrations in the south. But it was necessary first to find out where the Japanese were located and in what strength they were. To do this it was decided to push down the coast towards the Japanese road head at Mawaraka and at the same time extend inland to test the Japanese strength along the few existing tracks leading to the south. Troops of the 15th Battalion (29th Brigade) had taken over the Jaba River line from the American division. On the northern bank of the river they faced the Japanese on the other side.

On 19 December the 29th Brigade commander (Brigadier R. F. Monaghan) pushed his troops across the Jaba without opposition and made a landing from three barges some 4000 yards down the coast. It was the first move of the campaign proper. The coastal drive to Mawaraka was on. At the end on 1944, the Australians began to meet well equipped infantry who had evidently moved up from the south. The spearhead of Australian advance was provided by the 15th Battalion with the 42nd and 47th Battalions pushing inland to establish firm bases on the south bank of the Jaba.

The country there was flat, with thick jungle, swamps, and a multitude of small streams criss-crossed by native pads. In the New Year the characteristic Japanese tactics of infiltration, ambush and attack came to the fore and the fighting began in earnest. Twenty-five-pounders came in as support but the flat nature of the country prevented the setting up of observation posts, and most of the shooting was done by forward observation officers working with infantry patrols.

On 7 January the 61st Battalion (7th Brigade) relieved the 47th Battalion on the Jaba so that it could take the lead in the brigade advance. At the Adele River Australian troops came within range of Japanese artillery for the first time. On l2 January, preceded by an air strike, the 47th Battalion seized the mouth of the Hupai River and a log-crossing 800 yards inland. The brigade now began patrolling and consolidating, and patrols pushed forward to a sunken barge a few hundred yards north of Mawaraka. The 42nd Battalion took over and by 18 January Mawaraka was occupied without opposition but heavy fighting took place before the Japanese were cleared from the Pallisade area along the road towards Mosigetta. The following day the 1st New Guinea Infantry Battalion pushed round Gazelle Harbour, turned Motupena Point, and overcame an Japanese observation and listening post. The door was open for the drive inland.

While the resistance in the southern sector was increasing daily, although without sign of the formation of any general defensive line, the Australians turned once more to the inland sector about Doiabie. On the 30 December 1944, all four rifle companies of the 25th Battalion (7th Brigade) which had taken over from the 9th Battalion converged on Pearl Ridge, the focal point. Two companies attacked from Artillery Ridge on the right flank, one in the centre, and the fourth to the rear to sit astride the Japanese line of communication with Numa Numa.

Japanese fire pinned down the forward company advancing along Artillery Ridge. The men dug in and reorganised. The following day the main attack developed from the left and by mid-afternoon the Japanese had been cleared. Five days later the 11th Brigade (under Brigadier Stevenson) took over the central and northern sectors and 26th Battalion took over the line.

With the fall of Mawaraka the next step was to clear the way to the Puriata. The task fell to 7th Brigade (under Brigadier J Field) and on 23 January the 29th Brigade was relieved. The first move was an inland thrust to secure Mosigetta and drive the Japanese from the area. On 25 January Twen Force, comprising C and D Companies of 61st Battalion, pushed inland along the Pagana River in the direction of Kupon. Farther inland the commandos were denying the Japanese the track system running through Mosina, Nigitan, and Sisiruai. The 9th Battalion left Mawaraka next day and struck east towards Mosigetta along the south bank of the Hupai.

Within a fortnight 61st Battalion had penetrated Nigitan and Mosina, and turned south towards the 9th Battalion objective. Seven days down the track from Mosina saw the 61st poised near Mievo, a few hundred yards north of Mosigetta. Meanwhile along the Mawaraka-Mosigetta Road the going had not been easy for the 9th Battalion. Feeling a way through jungle swamps often shoulder-deep, pinned down in the mud, sleeping in water, and hampered by a supply line kept open only by the sweat of the native carriers and by the tractor towed jeep trains, they broke into Mosigetta on 16 January, half an hour ahead of the force moving down from Kupon.

On 24 January, the 25th Battalion relieved the 47th on the Tavera River. The same day a platoon from D Company landed at Motupena Point and set off down the coast towards Toko. By 3 February the platoon had closed to within half a mile of Toko and established itself on a lagoon. That day another platoon landed from a barge and the force, carrying the sandbar at the point of the bayonet, swept into the area which was to become the base for divisional operations in southern Bougainville.

From Toko a reputedly jeep-able track ran inland a few hundred yards above the Puriata in the direction of Darara on the No. I Government Road to Buin. This road was a continuation of the track south from Kupon through Mosigetta to Darara and on to the main Puriata ford. An eastward move from Toko towards Darara would close the river crossing, cutting the escape route of the Japanese retreating before the two battalions reorganising at Mosigetta for the Darara drive.

On the 10 February D Company was ordered to take Darara. At first the push was one of platoon strength; two others remaining at Toko to assist unloading through the heavy surf. It was not until the arrival of A Company and a platoon of the New Guinea Infantry Battalion that the position improved and the whole company got under way. It was a nerve-racking job. Twice the force was ambushed and attacked, and once while split into groups the Japanese swept in between. All the way the men had had to cut their own jeep track and on 23 February A Company pushed through and drove the Japanese from Darara. Patrols reached the Puriata and sealed the southern fords. The Japanese moved inland to escape across the northern fords, falling to the commandos in twos and threes. The way had been cleared for a shortened line of communication. Within a fortnight 7th Brigade established headquarters at Toko.

More and more air dropping came to the fore. At Piva strip, Torokina, the men of the Air Maintenance Platoon worked late into the night stowing the para-packs and free-drop rations. To maintain the road between Torokina and Toko engineers struggled against floods and a pounding surf which gnawed away at the coastline, washing out the road and breaking through the swamps. With Toko-Darara in Australian hands Brigadier Field prepared to cross the Puriata. On 25 February 9th Battalion was withdrawn for a well-earned rest at Motupena Point. From Mosigetta the 61st Battalion fought its way south-east, crossed the Puriata, and by 15 March was established in the Horinui region, threatening the approaches to No. 2 Government Road.

Early in January, 11th Brigade in the northern sector established a base at Amun and moved on towards Puto. The capture of Pearl Ridge in the central sector, the appearance of bulldozers, and the progress of Australian supply road led the Japanese to expect an eastern drive to Numa Numa. Natives from Teop on the Japanese -held north-east coast reported the evacuation of troops from the important northern bases of Ratsua and Pora Pora down the coast to Numa Numa. These reports and the fact that 11th Brigade had reached Puto without opposition suggested that the Japanese intended to evacuate the north entirely. However, by the middle of the month, the 31st/51st Battalion, between Puto and the Genga River, struck a hard crust of Japanese resistance.

In a series of sharp engagements the Japanese were driven north on to Tsimba Ridge to, the Amphitheatre, a curved knoll where the mountains pushed the coastal track into a narrow bottleneck against the sea. Here the ground, rising some sixty feet, runs inland over two hundred yards to a feature known as the Pimple. Before the ridge lay a native garden, behind was swampland. The Japanese had constructed 300 yards of defensive positions with fire lanes covering every approach. Despite artillery concentrations from guns of the 4th Field Regiment, the Japanese delayed the Australian advance for three grim weeks. On 23 January the Australians brought up a mountain gun and ripped away at the ridge. The Japanese replied by shelling Australian forward troops. The fighting was intensified and two days later, after a wide flank move, we succeeded in establishing a force on the northern bank of the Genga River. For nearly two weeks this force held out in the face of repeated counter-attacks. On the 6 February, under an artillery barrage and vicious fire from Japanese guns, the Amphitheatre was forced and the way opened to Matchin Bay.

In the last week of February the 31st/51st Battalion was relieved by the 26th Battalion, fresh from the central sector, and the next day contact was resumed. By 1 March forward elements were on the Compton River. The primary objective of the battalion was to clear the Japanese from Soraken Peninsula which protruded northward some two miles into Matchin Bay.

On 3 March an urgent message from a Corsair pilot patrolling the Ruri Bay area brought eight more planes roaring north from the Piva strip. After fifteen months of concealment, Japanese medium tanks had appeared! Heading across the Bonis Peninsula they were spotted on the road to Soraken plantation. By accurate bombing with thousand-pounders three tanks were destroyed and there were twenty Japanese killed in the strafing. In a matter of hours the tanks would have menaced Australian forward troops. A potential threat to the Australian flank was posed by Japanese artillery from the offshore islands of Saposa and Taiof.

On the night of 5 March A Company of the 26th Battalion embarked on the first of a series of amphibious operations which were to culminate in the crushing of Japanese resistance on the Soraken Peninsula. Troops went ashore on Saposa Island and within two days it was cleared. On 10 March they withdrew, leaving behind an infantry protected artillery observation post. The same night, farther to the north, native police cleared the Japanese from Taiof. The threat to the flank disappeared.

In the meantime the 31st/51st Battalion attacking up the coast had squeezed the main force into the defensive positions between the sea and where the Compton River turned parallel to it. Under a withering fire D Company attacked the centre, gained some ground and dug in. The 25-pounders of 4th Field Regiment settled down to blast the Japanese who withdrew on the night of 16/17 March. Meanwhile A Company again went ashore unopposed, this time near the base of the plantation. The following day contact was made with C Company which had pushed in from the south. The Compton River was crossed and the Japanese line of communication cut.

This section is from the Vetnet site http://www.onthenet.com.au/~vetnet/bouganvi.htm