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 [Torokina Airfield, Piva Yoke and Piva Uncle]. 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The two American divisions were gradually withdrawn for operations in the Philippines; and by the time the first of them, the 37th had quitted Bougainville the Australian campaign was under way.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 Munda. 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 November 7, 1944. On November 23, 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 roadhead 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 "jeepable" 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 thePuriata 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 Airfield,, 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 Airfield. 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.
On 4 March in the southern sector fire from mortars and medium machine guns supported "A" Company of the 25th Battalion to breach the Puriata at Galvin's Crossing and to establish themselves two hundred yards south along the main road to Buin. At noon the following day the Japanese shelled the area and the battalion suffered its first artillery casualty Pte Slater, after whom the knoll was named. For several days "A" Company attempted to move down the road without success. It was decided to send "B" and "C" Companies across the river on the right flank to establish firm bases in gardens around Old Tokinot. Such a move would cut the Buin Road in the rear of the Japanese and secure the Hatai track junction for a possible move up the track to link with the 61st Battalion in the Horinui region. At the same time, "A" Company would, within two days, clear the road and contact the outflanking companies near the junction. "B" and "C" Companies crossed the river and gained their objectives on the second day.
Experience at Tavera River, and along the track from Toko, had shown the Japanese policy to be comprised of sporadic small-party attacks, evacuation under artillery pressure, and a general attitude of "a live soldier is better than a dead one". With this in mind "A" Company struck out for the Hatai track to receive the first indication that the Japanese 6th Division, under Major-General Kanda, had swung over to the attack.
While in the north in the first two weeks of March the Japanese were being forced back on the Compton River, he seized the initiative in the south and gathered momentum for the drive which culminated in the attacks of Easter week.
North of Galvin's Crossing a patrol reported a four-days-old bivouac area estimated to have held eighty Japanese troops. A jeep was ambushed. The Japanese refused to budge under shelling. This had not happened before. On 15 March "A" Company fought its way across Kero Creek and
with "D" Company in the rear held off three counter-attacks and a fourth the following day. It was now apparent that the road was solidly blocked. Though patrols from "B" Company at Tokinot had reached "A" Company a permanent line of communication could not be maintained. The time had come to make a determined thrust down the road. "A" Company on the east and "D" Company on the west were to move down the axis and contact a force moving up from "B" Company. After fierce fighting contact was made on the 19th. "A" Company went into a perimeter defence and "B" Company, turning about, made back for its firm base.
Within sight of the junction the force bumped into Japanese of unknown strength on the east of the road. The company commander went in to attack. The force, in patrol formation, was without bayonets, but they were borrowed from "D" Company platoons which were brought in behind.
The Japanese were in a deep defensive position, crescent-shaped. Attacking with bayonet, rifle, Bren and grenade, the first row was cleared and the Japanese were forced to retire from the second to the third before halting the Australians. It was then too late in the afternoon to increase the scale of attack, and although skirmishing continued for the next two days it was not until the 22 March, after an Auster pilot had dropped an area sketch and the position had been plastered by artillery and air, that "A" Company cleared the position. In this attack Corporal Rattey won the Victoria Cross [ read citation ]
The following week the Japanese began to reconnoitre all the approaches to the Puriata. Jeeps were ambushed. Rear echelons and a gun position were raided. After diversionary attacks on Australian positions along the Puriata the first blow fell on "B" Company of 25th Battalion, dug in
hard against Anderson's Junction, the corner of the Buin Road and the track to Hatai. The night before Good Friday booby-traps were exploded about the "A" Company perimeter, some two hundred yards in the rear. The next morning the water patrol south to Dawe Creek was fired on and a patrol of twelve went out to investigate. This patrol was still away when the attack broke, and after several attempts to regain its perimeter was eventually ordered to "A" Company. Thirty-one remained in the "B" Company pits.
Towards the middle of the morning sixteen Japanese approached up the Buin Road. The first three were killed by the corner Bren-gunner. The remainder jumped into old Japanese pits on the south-west side of the road. Half an hour later a shower of grenades poured in from both sides of the junction. The Japanese opened up with everything. There were four attacks that morning; each one was pepped up in intensity. For the fourth the Japanese fixed bayonets and made an abortive banzai charge.
Reduced to twenty-eight and with ammunition low the defenders fell back on the "A" Company perimeter with the Japanese hard on their heels. The Vickers stopped the rush and the men, piling into the communication trenches, began to dig in furiously. That afternoon the Japanese again staged four attacks but all were repulsed. At night the Japanese set up the abandoned "B" Company mortars, and by tapping Australian wires managed to range on "D" Company which they plastered until morning. Night attacks continued on the encircled companies whose combined strength totalled eighty-three. Later estimates placed the attacking force at 550. All lines to battalion headquarters were cut.
At 9 am on Thursday and again on Good Friday advance tanks of "B" Squadron 2/4th Armoured Regiment went ashore at Toko from LCTs. On Thursday night Brigadier Field ordered the tanks to the Puriata. The following morning engineers of the 15th Field Company closed the three-ton truck bridge at Combes Crossing to traffic, and by 2.30 pm had a "tankable" bridge across the ditch. The tanks were delayed fifteen minutes. But the Puriata had flooded and although the level had fallen on Friday it was too high to ford the Matildas. The crews got to work and in half the time prescribed had waterproofed their vehicles. By 4.45 pm they were ready to cross. The first tank bogged and had to be abandoned. The other three crossed with the aid of a bulldozer, and moved on to 25th Battalion behind Slater's Knoll.
Next morning the tanks, escorted by infantry, engineers, and a bulldozer, set off for the invested companies. After surmounting all kinds of heart-breaking difficulties the track began to improve and the force pushed forward. In the perimeter the hard-pressed troops heard the engines roaring above the firing. Churning down the road the Matildas went in. Near the road the Japanese broke, and sweeping into the open, were mown down by the infantry. Moving closer in, the tanks' guns blew open the fox-holes and flayed the area with automatic fire while the infantry moved their wounded to the road. Here the force split, one tank escorting the wounded back towards Slater's Knoll, the others advancing with "B" Company to its old position to recover the heavy equipment. The force turned back and reached the other tank in time to beat off an attack on the wounded at a point where, earlier that afternoon, a jeep train had been ambushed. Too late to move farther, the men sheltered in the gutter along the road with the tanks drawn into the centre. The night passed quietly. The following day the weary companies returned to settle about the knoll, "C" Company withdrawing across the river from Old Tokinot to the Darara track.
The Japanese had shown his hand. Barbed wire was rushed from Toko and a further supply air-dropped. Above battalion headquarters "B" Company set about digging in on the knoll. Down the west bank to the south "D" Company went into the perimeter with "A". They did not have long to wait. At 5 am on 5 April the Japanese struck in force. Slater's Knoll, split left of centre by the Buin Road, is hard against the west bank of the Puriata bend. Approaching from the south, or Japanese side, the terrain descends to gully and rises quickly some thirty feet to a plateau approximately the size of two tennis courts. At the rear of the knoll the country drops abruptly to almost water-level; here battalion headquarters was established.
Striking in from the west a diversionary force hit battalion headquarters behind the knoll. It was quickly hurled back as the main attack developed. For an hour and twenty minutes the Japanese swept up in waves. Forcing the centre, he came within four yards of the forward pits. The company held firm. The troops, determined not to let the Japanese come any closer, fired standing upright in their pits. A small party attempting to cross the river were shot climbing the bank. Twenty-five-pounders joined in and by first light the sting had gone from the assault. The Japanese, pinned down along the wire, could be heard digging in the gully. An Japanese mortar opened close in, to be silenced by a Pita. All morning mortar bombs and grenades crossed and criss-crossed the wire. Sporadic attacks were broken up and the wounded were cleared away.
Below at headquarters the Japanese had long broken contact. A little after midday two Matildas moved through the cutting and the men of "B" Company came out to mop up. Small Japanese parties broke cover and were cut down. Japanese dead lay in heaps along the wire; they were found in an area two hundred yards square. The Puriata line was held. Farther inland after wide patrolling, the 9th Battalion (which had relieved 61st Battalion in the Horinui area) moved towards Rumiki and by 27 April was established on the next water barrier, the Hongorai, near the northern ford. After four months of fighting the weary 7th Brigade was relieved, and from 13 April the 15th Brigade, under the command of Brigadier H H Hammer, was set the task of clearing to the Hari. The initial step was to secure Anderson's Junction. With Matildas in support the 24th Battalion pushed down the road to Dawe Creek, and by 17 May the junction was in Australian hands. The advance moved on towards Shindou River and the 58th/59th Battalion sent patrols along the Hatai track to contact the 9th Battalion in the Rumiki area.
Fresh to Bougainville, the 2/11th Field Regiment came in with "U" Heavy Battery to strengthen the artillery support aleady being given by the 2nd Field Regiment. The 24th Battalion then began a series of tank-supported company leaps down the Buin Road and by the 7 May was established on the west bank of the Hongorai River at the Buin Road ford. The advance was forced against positions which had to be blasted by artillery, tanks and Corsairs of the RNZAF. Japanese 75mm. guns appeared as anti-tank weapons, usually manned by suicide crews. Land mines, booby-traps and shells buried nose-uppermost were also planted along the tracks. When these proved ineffective an unsuccessful banzai attack was made on "D" Company of the 24th Battalion.
Meanwhile in the Rumiki area 57th/60th Battalion had relieved the 9th Battalion and was deploying west of the Hongorai on the axis of Commando Road. All battalions had been most active in their patrols and the area between Commando Road in the north and for several miles south of the Buin Road had been made untenable by the Japanese. Thus he was forced to concentrate his troops along the two main tracks. This was greatly to Australian advantage for they now became excellent targets for Australian planes and artillery.
Towards the end of May the 15th Brigade prepared to strike for the Hari River down the axis of the Buin Road and down Commando Road simultaneously. The Japanese had every intention of holding the Hari, but threatened with a bold wide outflanking movement on the northern axis by 57th/60th Battalion, continually battered by Australian artillery and planes, and unbalanced by a series of outflanking moves along the main: road, by the 24th and 58th/59th Battalions, his defences collapsed and a spectacular advance took Australian forces across the Hari to the Ogorata to within striking distance of the Mobiai.
On 13 May a company from the 24th Battalion crossed to the east bank of the Hongorai and dug in near the ford. The 15th Brigade decided to hold the Japanese at the ford and create a diversion north of the junction of the Hongorai and Pororei rivers while at the same time the 24th and 58th/59th Battalions were to cross the river south of the Buin Road and attempt to come in behind the main Japanese defences which dominated the ford. Meanwhile, the 57th/60th Battalion would continue the advance down Commando Road and link up with the battalions advancing along the Buin Road. On 17 May the 57th/60th Battalion began its advance after an air attack by thirty-two aircraft and preceded by successive artillery concentrations. After some resistance the Japanese withdrew to the
The forward company settled down and the rear advanced through it to Huda River. Another force, completing a wide outflanking move, came in from the north to attack a strong position astride the road about half a mile south-east of the Huda. The Japanese resisted fiercely and the
position was occupied only after a fierce fight. A third force moving to cut the line of retreat broke through to the Torobiru, completing an advance of 3700 yards in one day. Two days later, the battalion, entrenched along the river, threw out a company to within 500 yards of the Uso-Oso junction and Winchester junction. Another patrol moving back cleared Tiger track to the Hongorai.
In the meantime, on theBuin Road, the company of 24th Battalion across the Hongorai on the main road was confronted with a strong force dug in on Egan's Ridge. Against the ridge Corsairs of the RNZAF. mounted an eight-day attack which put 381 aircraft over the area. The Japanese were led to expect a frontal assault down the road and an outflanking move to the north via Martin's crossing, but under cover of the intense air and artillery attacks on Egan's Ridge, a bulldozer cleared a secret track to Mayberry's crossing south of the river junction. The Japanese failed to discover the presence of the track, the noise of the 'dozer working being covered by the air and artillery bombardments. On the 20th the 24th Battalion with a troop of tanks crossed the river north of Mayberry's crossing and advanced north-east to cut the Buin Road on either side of the Pororei ford. Next day the 58th/59th Battalion with two troops of tanks crossed the river at Mayberry's crossing, and, advancing over difficult country against determined opposition, reached Aitara track to cut the road on the Japanese side of the Pororei. "B" Company settled down at the Aitara junction and an armoured force moved back along the Buin Road to contact "A" Company of 24th Battalion at the Pororei ford. En route the point tank opened up on the Japanese position and when the infantry went in they found a 7S-mm. gun sighted in the direction of Egan's Ridge. The Japanese had been taken in the rear. In the meantime, another armoured force in the 24th Battalion area cleared back towards the Hongorai, and after a preliminary bombardment "C" Company, which had crossed at the ford, moved up to the ridge. In a two-days' sweep the Hongorai and Pororei had been crossed, the track cleared to Rusei, and the southern end of Hammer Road secured.
In the north the 57th/60th Battalion had cleared the Uso-Oso track junction and the lateral link was opened when patrols from 24th and 58th/59th Battalions contacted 57th/60th Battalion near Winchester junction. The opening of this lateral link increased the effectiveness of the force pushing along the Commando Road. Medical evacuation was reduced by eight hours and it was now possible to supply the 57th/60th Battalion from the main artery. Further, it enabled tanks to move up in support for the drive on the Tai Tai gardens.
Around Tai Tai the Japanese had some 3,000 acres under cultivation. On 2 June the 57th/60th Battalion took the first step in its capture. Employing the same tactics of direct approach and flank attack the force swept down on the Tai Tai track junction and on 10 June came out below
On the Buin Road the 58th/59th was jabbing for the Mamagota junction. Subject to daily attacks and a host of obstacles including mines, booby-traps, tank ditches, and rough terrain, the troops gained a position west of the Tomoi. For the first time in the campaign the bridge-laying Scissors tank was employed. On the 3 June the Tomoi was crossed and the battalion moved to within 1500 yards of Mamagota junction. Two days later it was in Australian hands, and by the end of the week the northern and southern forces had made contact. The brigade poised before the Hari.
With prisoners reporting 1500 Japanese dug in east of the Han, supporting arms began plastering known positions. As at the Hongorai River another encircling move was planned with a frontal assault along the road by 58th/59th Battalion. From the north the 57th/60th was to go
through the jungle to the east and south in a wide arc to cut the Japanese line of retreat on the east of the Ogorata River near Rusei. Farther still to the north, an armoured patrol known as Scott Force was to thrust along Commando Road in the direction of Kingori as north flank protection.
The frontal assault met tenacious resistance from strong Japanese rearguards and the advance was halted. "A" Company, after clearing many mines and booby-traps, crossed the Peperu, but struck the Japanese on an escarpment and came under heavy fire. A 'dozer, trying to clear a path, might have had to be abandoned if it were not for the covering artillery support during which a tank retrieved it. Towards dusk the company pushed up and occupied the ridge temporarily evacuated by the Japanese. Both "B" and "D" Companies struck trouble. Although "B" Company broke through on the following day to the main Hari ford no further progress could be made. So, on the 7 June the 58th/59th Battalion was occupying the west bank of the Hari river from the ford northwards to Hari No. 3, and was opposed by the Japanese in strong positions along the east bank.
The companies settled down to patrolling and a new plan was evolved. This aimed at pushing Pike Force ("A" and "C" Companies) across the river near Pepib with the object of descending on the road at Hari No. I. "B" Company would then move through and open the road. Finally "D"
Company, with tanks, would cut the axis between Pike Force and the ford. The attack fell as planned. The fords were subjected to bombardment from artillery, mortars and planes, while the 24th Battalion and tanks were sent south across the river--a move calculated to delude the Japanese into thinking that the Hongorai crossing was about to be repeated. Pike force cut the road without sighting a single Japanese. "D" Company forced the steep bank at Hari No. 3, and, cutting the road, moved back to trap the Japanese at the main ford. "B" Company crossed the river, linked with "D" and the battalion moved through to consolidate on the Ogorata. The entire operation lasted three days. The Hari had been crossed.
Simultaneously in the north 57th/60th Battalion cut a path through unmapped territory east towards the Ogorata. At 8 am on the second day the force struck Barret's track and a two-hour fight with the Japanese ensued. Troops were deployed to hold the lateral tracks and while the
fighting was hottest the main body crossed into the jungle on the far side, moved 500 yards farther east and wheeled to the south. Farther to the north Scott Force had been ordered to slow down in order not to warn the Japanese of the move. The force turned down Barret's track with orders to find the 57th/60th communication wires and rejoin.
Brushes with the Japanese continued and on the night of 13 June the weary battalion settled down to sleep in the water, the ground being too boggy for digging in. In thirteen days the force had moved 13000 yards, and the next day the road was cut without opposition east of Rusei.
By 16 June the two battalions had linked on the road, with the 24th Battalion moving up in rear. Stores came down the road and the 57th/60th, supported by tanks and 2/11th Field Regiment, prepared to thrust for the Mobiai.
Late in the afternoon "B" Company set off. Four hundred yards from the start point the leading tank, tracking round a corner, received three direct hits from a 150-mm. gun. The Japanese then began shelling the road. The company reorganised and struck at the high ground on the left, only to be forced back. All night artillery and mortars pounded the defences across the depression. Next day the bulldozer broke down, and while it was being repaired patrols combed the area. A two company right flank encirclement got under way after the usual air bombardment. Without much opposition it cut the road behind the defence position. The following day the advance continued under heavy Japanese mortar fire. On the 23 June "A" Company of the 57th/60th dug in on the Mobiai.
Meanwhile, far to the north above Musakaka, and near the commandos at Morokia-mori, a self-contained force known as Atkinson Force had been patrolling across the Mobiai and Mivo. Operating since 7 June, in country thick with Japanese, the force continued to supply valuable information of Japanese movement on the outer flank. "C' Company of the 24th Battalion (Grahame Force) was five days late relieving them, due to continual Japanese attacks. In the last prolonged attack "C" Company, down to its last grenades, was ready to retire when the "sky train" came over and dropped ammunition into the perimeter.
The 58th/59th Battalion relieved the 57th/60th which returned to Rusei. The following day engineers threw a tank crossing over the Mobiai and cut a path to Killen's track. On 28 June the force moved forward to an assembly area, and the next day under a lifting barrage, the road was
cut and cleared east and west. By the last day of the month the troops were on the Mivo River, and the relief of the 15th Brigade by the 29th Brigade began.
As soon as the relief had taken place the Japanese made several determined attack s across the river. In the nrth, on Killen's track, the 47th Battalion repulsed four vigorous attacks, and, on the Buin track just west of the Mivo ford, the 15th Battalion defeated three more.
From the time the 29th Brigade under Brigadier Simpson took over, the story of south Bougainville was one of constant struggle against waterlogged tracks and supply difficulty. From 11 July until early August very heavy rains restricted activities. By the 22nd all rivers were in flood, the Mivo rising to seven feet at the ford and flowing between twelve and fourteen knots. During July twenty-six days were wet and 2193 points of rain fell. Both sides settled down to deep offensive patrolling, with the Japanese pushing a strong force back into the Tai Tai garden area to harass Australian lines of communication.
Meanwhile in the northern Bougainville, the 26th Battalion, following the Compton River defeat of the Japanese, quickly cleared the Soraken Peninsula. In April the 23rd Brigade, which had been in the outer islands, took over on the central sector, enabling the 11th Brigade to move a second battalion forward in the north. The 55th/53rd Battalion sent one company over a rough track along the mountains to close in on Pora Pora while the rest of the battalion pushed along the axis of the coastal track, encountering strong Japanese opposition at first. Finally the Japanese withdrew and Pora Pora was occupied on 3 May. One company then moved west and seized Ratsua jetty. By 11 May the road junction at Ruri Bay was secured and the Japanese were contained within the Bonis Peninsula by a line of defended localities between Ratsua and Ruri Bay. On 19 May 55th/53rd Battalion was relieved by the 26th Battalion and on the 3 June the 31st/51st Battalion came forward from Torokina to assist in strengthening the line across the base of the peninsula.
The Japanese were holding Buoi Plantation in strength and in an attempt to outflank it by movement from the sea one company from the 31st/51st Battalion landed at Porton Plantation at 4 am on the 8 June. Unfortunately the second wave of landing craft stuck fast on the reef about seventy-five yards offshore. The landing party penetrated into the plantation but immediately met withering fire from Japanese machine guns fired at close range. At the same time machine-gun fire was directed from the northern foreshores on to the stranded landing craft, preventing the unloading of stores and ammunition. Patrols inland were unable to make head way against the heavy fire of the now reinforced Japanese who next surrounded the perimeter and heavily attacked it from the north and east simultaneously. Forward observation officers brought down heavy supporting fire from Australian artillery, many of the shells falling as close as twenty-five yards in front of the defending troops.
During the night further attempts were made to land ammunition and supplies on the beach, but all night long the shore was swept with murderous Japanese fire and the stranded barges were continuously the target for intensive bursts from machine guns. The troops manning the small perimeter were attacked many times, but they gallantly resisted all Japanese attempts to break their line. Ammunition was quickly running out and it was decided to withdraw the force the next night but, after a night spent in repulsing counter-attacks, a very heavy attack early in the morning penetrated the perimeter and forced a withdrawal to near the beach.
The withdrawal was now more urgent and the vessels of the 42nd Landing Craft Company were sent in to run the gauntlet in daylight of increased Japanese fire. They succeeded in withdrawing sixty of the garrison. During the night further attempts were made to take off the remainder but only partial success was achieved. On 10 June under cover of a heavy bombing attack and a continuous artillery barrage, craft made the beach in the late afternoon and during that night the withdrawal was completed. The Japanese strength had been greater than was anticipated, and they were able to reinforce the threatened area quickly. In the many vicious attacks on the perimeter the Japanese suffered heavily from the fire of Australians fighting one of the toughest defensive actions of the campaign. The 23rd Brigade,under Brigadier A. W Potts) began the relief of 11th Brigade on 23 June and 11th Brigade moved back to Torokina for a well-earned rest. Following the Porton operation the Japanese became very aggressive and ambushed the Australian supply routes.
In southern Bougainville the time was fast approaching when the Japanese would be forced to fight the decisive battle and every opportunity was being taken to build up supplies and to rest troops in preparation for this. Little help could therefore be given to reinforce our troops in the north to protect their supply lines and it was decided to withdraw the 8th and 27th Battalions to an area near Ratsua, where supply problems would be more easily met and where patrols, operating from these bases, would effectively prevent the free movement of Japanese troops in or out of the Bonis Peninsula.
The last series of actions in which Australians were engaged on Bougainville were fought by the 8th Battalion, operating in the northern section with the object of sealing off the enemy in the Bonis Peninsula area. On the afternoon of 24 July two platoons attacked Base 5 after a bombardment in which 900 shells and mortar bombs were fired. The advancing troops reached the first ridge without difficulty, but then ran into heavy fire from well-camouflaged bunkers. At this point Private Frank John Partridge of the 8th Battalion on his own initiative single handedly
assaulted the Japanese positions. The citation for the Victoria Cross awarded to Private Partridge [ read citation ].
The 8th Battalion attack evidently shook the Japanese, and after cautious patrolling Base 5, which was renamed "Part Ridge", was occupied on 5 August after only slight opposition. There were more than sixty bunkers in the area. On 11 August active patrolling ceased in this and other sectors, and four days later the war ended.
At the same time, however, offensive patrolling continued, always with the object of collecting information which would ultimately enable the 23rd Brigade to come to grips with the determined Japanese in the peninsula. The end of hostilities came before this could be put into effect.
The 23rd Brigade along the Numa Numa Trail had continued the aggressive patrolling policy of previous brigades.
This continued offensive harassing reduced the morale of the Japanese troops. When it was known that many of the Japanese from the Bonis Peninsula were withdrawing along the eastern coast to Numa Numa, the time seemed opportune to increase the pressure along the Numa Numa Trail and to attempt to reach the coast. The 7th Battalion entered into the operation with a will and, ably supported by mountain guns, captured Smith's Hill on May 12 and by July 18 had driven the Japanese from Berry's Hill, Wearne's Hill and Tiernan's Spur and had established a company locality on the rolling ground on the far side of the dividing range from which patrols frequently reached the east coast to annoy and harass the surprised Japanese. This was the situation when the Japanese opened the negotiations which resulted in their ignominious surrender.
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