The Battle of Pearl Ridge (30–31 December 1944) was a battle of the Second World War fought between Australian and Japanese forces on Bougainville Island. Part of the wider Bougainville Campaign, the battle took place in the central sector of the island, shortly after the Australians had taken over responsibility from the Americans. Believing that the ridge was held by less than a company of Japanese, on 30 December the Australian 25th Battalion launched a four-pronged attacked the ridge. The defending force, however, had been greatly reinforced and was closer to a battalion in strength. After being held up on the right of their advance, the Australians dug in overnight and repulsed a strong Japanese counterattack before resuming the attack on 31 December. By late in the afternoon, the Jap