US Marines conducted an amphibious landing at Cape Torokina, on the western coast of Bougainville, north of Empress Augusta Bay, in November 1943. After an initial counter-attack that was repulsed, the Marines had been replaced by a garrison of US Army troops who began consolidating their position around Torokina, establishing a strong perimeter. In March 1944, the Japanese launched a heavy counter-attack, which was turned back with many casualties. After this, the situation on Bougainville became largely static, as the Japanese focused primarily on subsistence, and the US forces chose to adopt a mostly defensive posture aimed at maintaining the perimeter around Torokina.