 In September 1944 , the 27th Battalion was deployed to Green Island where they relieved the American troops defending Lagoon Airfield . The Americans were subsequently redeployed to the fighting in the Philippines . In 1945 , the battalion moved to Bougainville to take part in the Australian campaign there . Initially , it was tasked with relieving the 55th / 53rd Battalion at <unk> River in the central sector of the island , which it did so in March . In April , the battalion pressed on to Pearl Ridge where they took over from the 31st / 51st Battalion and began to carry out patrols in front of the ridge . Over the course of six weeks , the battalion carried out a number of minor attacks and in the process captured several key features before moving to the northern sector of the island on the Bonis Peninsula around Ratsua where they continued to harass Japanese forces through active patrolling and ambushing . This continued until the end of the war in August 1945 . 
