Key Facts
- Initial phase dates
- 17 April – 22 May 1945
- Theatre
- Pacific Theatre, World War II
- Australian formation
- 15th Brigade
- Objective
- Japanese concentration at Buin
- Advance halted by
- Torrential rain and flooding
Strategic Narrative Overview
The battle unfolded in two phases between April and May 1945. In the initial phase, Australian forces advanced toward the Hongorai River. After early fighting subsided, the advance continued toward the Hari and Mivo Rivers. Torrential rain then caused severe flooding, washing out bridges and supply roads and bringing the Australian advance to a standstill. Japanese forces exploited the pause by harassing Australian lines of communication, while preparations were made to resume the advance once conditions improved.
01 / The Origins
Following the Allied strategy to neutralise Japanese forces on Bougainville Island, Australian forces of the 15th Brigade were tasked with advancing south along the Buin Road in the island's southern sector. This operation came after the Battle of Slater's Knoll, where a major Japanese counterattack had been repelled, and aimed to press toward the main Japanese stronghold at Buin as part of the broader Bougainville Campaign in the Pacific Theatre.
03 / The Outcome
As flooding subsided in late July and into August 1945, Australian forces began preparations to resume the drive toward Buin. However, Japan's surrender brought the war to an end before the final Australian advance could be launched, effectively concluding the Bougainville Campaign without a conventional military resolution in the southern sector. The planned objective at Buin was never taken by force.
Belligerents & Mobilization Analysis
Side A
2 belligerents
Side B
1 belligerent
Kinetic Engagement Axis
Scroll horizontally to view full axis. Events plotted relatively.