The Battle for Piva Trail was a battle between United States Marine Corps and Imperial Japanese Army forces on Bougainville Island. The battle took place on 8–9 November 1943 during the Bougainville campaign of the Pacific War in the days following the US landings at Cape Torokina earlier in the month.
The fighting took place inland from the US beachhead, as the Japanese began moving troops from the 23rd Infantry Regiment north from southern Bougainville. These troops subsequently clashed with a blocking force of US Marines that had been positioned along the Piva Trail to protect one of the key avenues of approach towards Cape Torokina. It had been intended that the 23rd Infantry Regiment would coordinate their assault with a counter landing at Koromokina Lagoon, but ultimately this did not occur as the main assault was delayed until after the counter landing was defeated. The fighting for the Piva Trail resulted in heavy casualties for the Japanese and was followed by a series of actions throughout November and December 1943 as US forces sought to expand their perimeter around Cape Torokina.
Background
In early November 1943, US forces had landed around Cape Torokina and established a beachhead, as part of Allied efforts to advance towards the main Japanese base around Rabaul, the isolation and reduction of which was a key objective of Operation Cartwheel. Facing the American beachhead at Cape Torokina were troops of the Japanese 17th Army, commanded by General Harukichi Hyakutake, the main elements of which were drawn from Lieutenant General Masatane Kanda's 6th Division. In response, the Japanese attempted a counter landing at Koromokina Lagoon and began moving reinforcements north from southern Bougainville.
To protect the narrow beachhead while further reinforcements and supplies arrived, the U.S. 2nd Marine Raider Battalion advanced inland and set up a roadblock on the Piva Trail, around the junction with the Numa–Numa Trail, one of the key avenues of approach towards Cape Torokina. In an effort to reinforce the troops landing around Koromokina Lagoon, the Japanese 23rd Infantry Regiment, advancing from southern Bougainville, was tasked with dislodging the US troops holding the Piva Trail. The Japanese intent had been to coordinate actions on both sides of the US perimeter, but ultimately the landing around Koromokina Lagoon was defeated before the 23rd Infantry Regiment could mount a full-scale attack against the Marine defenses along the Piva Trail.
Battle
On the night of 5–6 November, the Marines drove off two preliminary attacks from the Japanese 23rd Infantry Regiment. Colonel Edward A. Craig, commander of the 9th Marines to which 2nd Raider Battalion was attached, surmised that this was just a preparatory action and brought up more Raiders to reinforce the roadblock. When the Japanese attacked the following afternoon (7 November), the Marines were ready and drove the Japanese back to Piva village. Early on the morning of 8 November, Major General Shun Iwasa, commander of the Japanese 6th Division's infantry group (the Iwasa Detachment), renewed the attack with two full battalions. The Americans brought up men of the 3rd Raider Battalion to protect the flanks of the Marines already engaged, as well as some light tanks. Frontal attacks by the Japanese were repulsed.
Major General Allen H. Turnage, in command of the 3rd Marine Division, determined that the Japanese lodged on the trail represented a threat to the airstrips and had to be removed, with the assault beginning on the morning of 9 November. The Japanese had several well-placed machine guns and were attempting an attack of their own; a bloody stalemate developed. Private First Class Henry Gurke of the 3rd Marine Raider Battalion was awarded the second Medal of Honor of the Bougainville campaign during this fight by throwing himself on a grenade and saving his foxhole-mate. Marine firepower eventually proved too much for the Japanese, who retreated to and through Piva Village in the early and mid-afternoon. The Marines took possession of the vital intersection of the Piva and Numa Numa Trails.