An account of the Militia at war
The largest of the Solomon Islands is Bougainville. It is 120 miles long and 40 miles in width at the widest part. The mountain chain which forms its backbone rises to 8000 metres at Mount Balbi, an active volcano. The main population areas are in the southeast and east in wide flat country with high forest and dense undergrowth covering the rest of the island to the 4500 metre contour here scantier moss forest begins. The temperature is generally hot and humid although the beaches are pleasantly cool at night.
On 1 November 1943, the US 3rd Marine Division landed at Torokina on the northern side of Empress Augusta Bay and secured the beachhead. The Marines were relieved by the US XIV Corps on 15 November. In March 1944, a full scale Japanese offensive against the American positions was repulsed but the Americans did not extend their perimeter further and were in the same positions when the Australian II Corps under the command of Lieutenant General Stanley Savige took command in December 1944. In late 1944, the Americans estimated that 12,000 Japanese remained in the islands, the Australians estimated that 25,000 remained but in fact there were 40,000 of whom 8,000 were in the forward area.
The two US divisions on Bougainville were replaced by four Australian brigades, the 7th, 15th and 29th Brigades of the 3rd Australian Division and the 11th Brigade. The 15th Brigade had some 16 months operational service by the time it reached Bougainville. All were militia brigades that had seen heavy fighting in New Guinea. The militia was the pre-war citizen forces which had been called up for full time duty and was separate from the AIF which had been specially raised in 1939 for overseas service. By 1945 many militia soldiers had volunteered for the AIF and when 65% of a unit had volunteered, the unit was entitled to be called an AIF unit. Eight of the 12 battalions in these brigades were Queensland units - all the militia battalions from that State. Although reinforcements were sent to battalions without regard to the state in which they were raised, more than half of the men in each unit still belonged to its home State. The burden of the Bougainville campaign thus fell particularly heavily on Queenslanders.
The main Japanese force was concentrated in the south of the island but it was in the central sector along the Numa Numa trail that the Australian campaign opened. The Numa Numa trail traversed the island from the Torokina perimeter along a gorge, up an escarpment then along a saddle of the main range to the east coast. The 9th Bn (7th brigade, 3rd Division) relieved the Americans above the escarpment on 22 November 1944 and a week later captured the nearest Japanese position. With both air and artillery support, the next position, arty Hill, was taken on 18 December when the Japanese left 25 dead. The 25th Bn relieved the 9th Bn and took the next feature, Pearl Ridge a few days before the 11th Brigades took over the central sector on 1 January 1945. The Australians could now see the sea on both sides of the island from the newly won positions but were restrained from advancing further and held their positions while heavily patrolling the forward areas. Each of the battalions of the 11th Brigade did a tor of four to six weeks in the central sector - the 26th Bn until 2 February; the 55th/53rd Bn until 15 March; and the 31st/51st Bn until 18 April. The second battalion of the brigade during this time was in the northern sector and the third was resting.
In April 1945, the 23rd Brigade (7th, 8th and 27th Bns), having moved to Bougainville from the outer islands, replaced the 11th Brigade in the central sector. The 27th Bn patrolled deeply but was under orders not to attack in strength. In six weeks, it made 48 patrols and killed 122 Japanese for the loss of 4 killed and 9 wounded. The 7th Bn relieved the 27th Bn in June and was given a more active role. Advancing from Pearl Ridge, the 7th Bn attacked and captured a series of Japanese positions. It took McInnes Hill in August and used strong patrols to probe deeply into Japanese territory.
In January 1945, the 31st/51st (11th Brigade) advanced north from Sipaai and ran into the Japanese on Tsimba Ridge, forward of the Genga River and some five miles south of Soraken. On 6 February in an attack preceded by artillery and mortar barrages the ridge was captured. The last pocket of resistance was not overcome until the next day. 66 Japanese were killed in the fighting and 7 pieces of artillery and 9 machine guns were captured. The Australians moved forward with air and artillery support and captured the ridge overlooking Soraken on 19 February 1945. Two days later, the 31st/51st Bn which had suffered 34 killed and 19 wounded in six weeks of fighting was relieved. During March, the 26th Bn cleared the Japanese from the Soraken Peninsula and nearby island in hard fighting that obtained good observation of Soraken Harbour and Buka Island. In early April 1945, the 26th Bn was relieved by the 55th/53rd Bn. It moved towards Pora Pora with one company advancing along the coast and another along an inland track. It pushed the Japanese back to a line from Ruri Bay to Ratsua Inlet stretching across the neck of the Bonis Peninsula. Late in May 1945 the 26th Bn relieved the 55th/53rd Bn and continued northward but met opposition so stern that the 31st/51st Bn was again brought forward. The Japanese doggedly resisted the Australians who by now were weary and far below strength. On 8 June, a rein-forced company of the 31st/51st, in 6 landing craft, tried to outflank the Japanese by landing behind the lines at Parton but was forced to withdraw after 48 hours, having lost 23 killed and 106 wounded.
The 11th Brigade was relieved at the end of June by the 23rd Brigade which was ordered to contain the Japanese in the Bonis Peninsula and to patrol towards Buka passage. Initially, the 8th and 27th Bns operated on separate sides of the peninsula but deadly Japanese raids ambushed ration parties and cut signal wires behind Australian lines.
On 21 July 1945, the 27th Bn recorded that it had suffered 10 killed and 34 wounded in the previous month although it had made no forward movement. Approval was given on 22 July for the 23rd Brigade to concentrate on a 3,000 metre front around the Buoi plantation. On 23 July, the 8th Bn with air and tank support attacked a ridge that the Japanese had strongly entrenched. Next day, another attack was halted by heavy fire from well camouflaged positions until a wounded 20 year old Private Frank Partridge dashed forward knocking out one bunker and leading the attack against a second. He was awarded the Victoria Cross. The Japanese later abandoned the position.
The 3rd Australian Division was given the role of destroying the Japanese in south Bougainville. In late November 1944, the 29th Brigade (15th, 42nd and 47th Bns) replaced the Americans north of the Jaba River and began extensive patrols. On 28 December 1944 the brigade was given the task of advancing south along the coast. The Japanese resisted the advance but the Australians steadily gained ground. By mid January 1945, the brigade had advanced 13 miles and secured the coast as far south as Mawarak which was entered without opposition on 17 January. The brigade was relieved on 23 January by the the 7th Brigade (9th, 25th and 61st Battalions) which continued the advance towards the Puriata River.
The 9th Bn advanced towards Mosigetta against Japanese tactics of fighting from ambush positions flanked by swamps and dense bush, mining the road, cutting signal wires and night counter attacks. The Australians responded with mortar and artillery fire but if this failed, wide and deep outflanking moves were made. Although losses were not heavy, conditions were extremely uncomfortable and there was a constant sense of danger. The 61st Bn linked up with the 9th Bn at Mosigetta on 17 February 1945 and by 1 March patrols from both battalions and a detachment of the 25th Bn had reached the Puriata River along a wide front.
The 25th Bn crossed the Puriata River on 4 March 1945 and soon ran into heavy Japanese resistance. The Battalion established its base close to where the Puriata converged with Buin Road at Slater's Knoll. The Japanese were strongly dug in along the Buin Road and fired some 600 shells at Slater's Knoll in March 1945. A company advancing along Buin Road was surrounded and persistently attacked for three days. The 25th Bn attacked on a two company front on 19 March and forced the Japanese back from their positions to an extensive system of pill-boxes at a road junction. On 22 March, after air and artillery bombardments the new position was attacked. During the attack Corporal Reg Rattey, using a bren gun and grenades, knocked out 4 pill-boxes. He was awarded the Victoria Cross; the first won by a member of a militia battalion.
Intelligence indicated that the Japanese would launch a major offensive in April 1945 with the brunt falling on the 25th Bn. The attack was prefaced by a series of raids on the lines of communications and on troops in the rear. The positions of the 25th Bn were probed and attacked from 27 March. The offensive culminated with a major assault against Slater's Knoll on 5 April. In10 days fighting 620 Japanese were killed and about 1000 were wounded. The 7th Brigade was relieved after 10 weeks in the front lines during which the 25th Bn suffered 10 officers and 179 other ranks killed and wounded.
A lull followed the Japanese offensive. The Japanese were exhausted and the 15th Brigade (24th, 57/60the and 58/59th Bns) was not able to attack until the roads were upgraded so that supplies could be brought forward. On 17 April, 15th Brigade opened its advance with the 24th Bn on the Buin Road and the 57/60th on Commando Road. At first, resistance was light but as the Australians neared the Hongorai River it stiffened with forward infantry coming under frequent artillery fire causing casualties. After three weeks of fighting to gain 7000 yards, the Hongorai River was reached on 7 May. The cost had been 120 killed or wounded; 169 Japanese dead were counted.
From the Hongorai River to the Mivo River
The 15th Brigade patrolled deeply in the middle of May with the main crossing of the Hongorai River beginning on 20 May. The Japanese were forced from the ridge overlooking the river and the main advance resumed on 2 June behind deadly air and artillery bombardments. Patrols were on the Hari River by 5 June but when the main body of the 58/59the advanced along the Buin Road it met heavy fire and the tanks were delayed by boggy ground. Meanwhile, the 57/60th moved along Commando Road and by mid June both battalions were beyond the Hari. The Japanese put up a strong defence in front of the Mobia River which was reached on 25 June. The next objective was the Mivo River which was reached by a series of wide flanking moves carried out with few casualties. However, many minor battles were fought by the 15th Brigade between the major ones and its losses were heavier than any other brigade on Bougainville - 32 officers and 493 men killed or wounded.
During the 3rd Division advance from the Jaba River to the Mivo River, the 2/8th Commando Squadron protected its flank. Further inland, the AIB, led by Australians but with native guerillas, created a reign of terror among the well-armed and trained Japanese troops. It is estimated that this force killed over 2,000 Japanese in eight months of operations. The 29th Brigade came back into the front lines and was to cross the Mivo River on 3 July but continuing heavy rain caused a series of postponements. Before the offensive could be launched, active patrolling ceased in all sectors of Bougainville on 11 August. A Japanese envoy entered Australian lines on 18 August but Australian minesweepers at Moila Point were fired upon on 20 August and the Japanese commander waited until the surrender at Rabaul in New Britain on 3 September 1945 before surrendering his Bougainville command.
During the whole of the Bougainville campaign, 516 Australians were killed or died of wounds and 1,572 were wounded. Of the 65,000 Japanese who were on the island when the Americans attacked in 1943 only 24,000 survived.
