II Corps. The battalion then began an offensive campaign which saw them involved in heavy combat with the Japanese. They were committed to the fighting in three periods. The first, between December 1944 and February 1945, saw the battalion take Tsimba Ridge, cross the Genga River and capture Downs Ridge. Later, in March and April 1945, they undertook long range patrols in the central sector of the island in the vicinity of the Numa Numa Trail. Their final commitment came between May and July 1945 when the battalion was switched to the northern sector, where they took part in the fighting around the Bonis Peninsula. As a part of this phase, the battalion fought along the Ratsua front and undertook a disastrous amphibious landing at Porton Plantation. Conceived as a company-level effort to outflank the significant Japanese defences that were holding up the advance from Ratsua, the operation was plagued by poor planning, inadequate resources, intelligence failures and strategic and tactical errors at all levels. After landing at the wrong beach on 8 June, and finding themselves caught in a tight box of Japanese defensive positions, the 190 men from 'A' and 'C' Companies, under Captain Henry Downs, were unable to advance inland. One of the landing craft ran aground and supplies began to dwindle. In an effort to link up with the beleaguered company, 'D' Company, which was holding the line along the Ratsua front, attempted to break through the Japanese lines. Although some patrols were able to penetrate to within of Porton, they were unable to get any closer. Eventually the order to withdraw was given from 11th Brigade headquarters. During the subsequent evacuation, two more landing craft ran aground and although one managed to float free, the other remained stuck hard on a reef. Over the course of the next couple of days, the men in the landing craft were subjected to heavy Japanese attack and it was not until 11 June that rescue efforts were completed. The battalion lost 23 men killed or missing, presumed dead, while a further 106 were wounded in the operation. Following the failure of the landing at Porton Plantation, the planned Australian advance into the Bonis Peninsula was called off, and the Australians focused their main effort on Bougainville towards the capture of Buin in the south. The effort in the north was reduced to that of a holding action as