Nassau Bay. The 162nd US Regiment landed at Nassau Bay on the night of the 29/30 June and next morning moved out of the bridgehead. On 1 July the easternmost company of the 2/6th Battalion advanced to the coast along the south arm of the Bitoi River, driving off a company of Japanese. On the morning of the third day ashore, 2 July, the main American force remained clustered round the beach, but that afternoon one company advanced to the Bitoi. Next day four 75-mm guns were landed at Nassau, a most important reinforcement, and by the 4th more than 1,400 troops were ashore. Papuan soldiers advancing along the coast ahead of the 162nd US Regiment reached Lake Salus on 9 July and then pushed on to Tambu Bay. On the morning of 7 July the 2/6th had attacked Observation Hill and by nightfall held most of it. Next day the leading Australian company advanced a stage farther towards a creek where it was to link with the Americans from the Bitoi. On the 9th, now supported by the American field guns whereas formerly there had been only two mountain guns behind them, five Australian companies pressed on with aggressive patrols until, on the 10th, only seventy-five Japanese survived in the area, and their line of retreat was cut. On the 12 May the Pimple was occupied. On 13 May there was a general advance and on 14 May Mubo airfield and Green Hill were taken. The Japanese still stoutly defended Old Vickers where they were strongly dug in to defend the track to Salamaua and on 7 and 9 July stopped attacks by the 58th/59th Battalion. The US III/162nd Battalion (Major Archibald B. Roosevelt) was assembled at Nassau Bay by 12 July as a preliminary move to establish artillery at Tambu Bay. On the 21st the American battalion reached Tambu Bay and supplies were being unloaded there. The Americans' task was to capture Scout Ridge, overlooking the bay. Attacks on the 22nd failed and a second battalion (the US II/162nd) was sent into reinforce the attack. On 16 July a company of the 2/5th Battalion had assaulted Mount Tambu with great dash and captured all but the main northern knoll. The Japanese counter-attacked again and again that night, supported by mortar bombs and shells from a mountain gun. A second company reached the area next morning. On the night of the 18 May the Japanese attacked and almost encircled the two Australian companies on Tambu, and next day a fierce struggle developed. By 2.30 pm, after much slaughter of the Japanese, they accepted defeat and left the Australians in possession of the southern slopes. Farther north, on 15 July, after mortar and Vickers-gun fire, two platoons of the 2/3rd Independent Company attacked Ambush Knoll south of Namling, while the 58th/59th Battalion attacked towards Bobdubi in another effort to cut the Japanese communications. One platoon of the Independent Company drove the Japanese from their forward positions, the other thrust them from Orodubi, and that night the Japanese abandoned Ambush Knoll. The attack by the 58th/59th was upset, however, by Japanese counter-moves. In a renewed attack on the 17th the Independent Company again carried out its task but the 58th/59th was held up. The establishment of the Nassau Bay base had made it possible to bring in and supply a substantial quantity of artillery. By 23 May two US field artillery battalions, two Australian field batteries, the 1st Australian Mountain Battery, the 2/6th Australian Survey Battery, and four anti-aircraft batteries were in place. On the right flank the American regiment was still making little progress. In the fourth week of July the US II/162nd battalion completed its arrival at Tambu Bay and was given the task of capturing 'Roosevelt Ridge' as it was now named. The battalion attacked and gained and held a foothold on the ridge. The Japanese were well dug in and not to be driven out by frontal attacks. Roosevelt's battalion, aided by Papuan patrols, was now employed cutting the enemy's supply route to the west. On 28 July a flanking attack by a company of the 2/6th took a feature forward of Ambush Knoll. The same day 58th/59th Battalion supported by artillery, mortar and machine-gun fire at last took the stubborn Old Vickers position and drove the Japanese from Bobdubi Ridge. It was estimated that in the six weeks to 6 August, the 15th Brigade had killed 400 Japanese for a loss of forty-six killed and 152 wounded, an indication of the increasing tactical superiority of the attackers. The leading battalion of the 29th Australian Brigade, the 42nd, was moved forward into the Nassau Bay area and thence marched northward and at length went into position between the Americans on the right and the 17th Brigade, of which it became part. As a preliminary to the capture of Mount Tambu the 42nd Battalion occupied Davidson Ridge between Tambu and Roosevelt Ridge. Then on 13/14 August the II/162nd Battalion took Roosevelt Ridge after a heavy artillery barrage which bared it of vegetation. The 15th Brigade's attack opened on 14 August. Twenty-nine heavy bombers accurately bombed Coconut Ridge with devastating effect, and guns, mortars and machine-guns brought down a barrage. A company of the 2/7th Battalion then attacked up a cliff so steep that the men had to crawl on hands and knees, but by early in the afternoon they had gained the North Coconuts position. On the night of the 16/17 August the Japanese abandoned South Coconuts. The 2/6th Battalion opened its attack on Komiatum Ridge on 16 August. After about 500 shells had been fired into the Japanese positions two companies attacked and in twenty-five minutes had occupied the objective. The enemy in the Mount Tambu area were now surrounded, their routes to the north being cut on Komiatum and Davidson Ridges. It was expected that lack of rations (patrols had discovered they were delivered every three days) would cause the Japanese to attempt the break out on the third night. On 19 August patrols of the 2/5th found Goodview Junction deserted and US I/162nd Battalion occupied Tambu without opposition. The 15th Brigade now pressed in towards the track leading to Salamaua. On 17 August after a bombardment two platoons of the 2/3rd Independent Company advanced; one occupied the junction of the Bobdubi-Salamaua track and another track from the south without opposition, but the other was held. Heavy fighting developed, the Japanese launching strong counter-attacks. On 19 August Savige ordered that every effort must be made to close the enemy's avenues of escape between Komiatum and Bobdubi Ridges. Next day the brigade attacked on a wide front, and the 58th/59th succeeded in cutting the Komiatum track in several places. In preparation for the new offensive, Savige was instructed that his force should be so organised that by 28 August it could be maintained from the sea without air supply. From 21 August the 29th Brigade began to relieve the 17th Brigade (excluding the 2/7th Battalion attached to the 15th Brigade) which had been fighting its way through the jungle-clad tangle of mountains from Wau towards Salamaua since January. The Australians rapidly advanced towards Salamaua but Savige ordered that the Japanese were not to be pressed so hard that would cause an early evacuation of Salamaua.