Battle of Porton Plantation

The Battle of Porton Plantation (8–10 June 1945) took place near the village of Soraken on Bougainville Island, in the Solomon Islands archipelago during World War II. Involving forces from Australia, New Zealand and Japan, the battle was part of the wider Bougainville campaign, which had begun in late 1943 and lasted until the end of the war in August 1945. The battle formed part of Australian efforts to liberate the northern part of Bougainville.

The fighting occurred after a company-sized Australian force from the 31st/51st Infantry Battalion made an amphibious landing north of the Porton Plantation jetties in an attempt to outflank the Japanese positions on the Ratsua front, which were holding up the advance of the 26th and the 31st/51st Infantry Battalions from the 11th Brigade. The Australians landed unopposed and established a small perimeter, but some of their landing craft ran aground and they were unable to bring their heavy weapons and support elements ashore. Troops from the Japanese 87th Naval Garrison Force quickly surrounded the beachhead and, as their supply situation grew desperate, the Australians were forced to withdraw. In the course of their evacuation by sea another landing craft ran aground. Over the next two days several unsuccessful rescue attempts were made until eventually, in the early morning of 11 June, the last Australian survivors were picked up.

The battle was a victory for the Japanese and it proved instrumental in helping them to regain the initiative in the northern sector of Bougainville. As a result, shortly afterwards the Australian forces on Bougainville changed the focus of their operations to the southern sector of the island where they were able to advance along the coastal plain towards the main Japanese position at Buin. Since the end of the war, there has been considerable criticism of the planning undertaken by the Australians prior to the operation, and it has been argued that the operation failed due to poor intelligence and lack of resources and was ultimately unnecessary.