An important element of the island hopping campaign, but like many other battles seldom mentioned, was one which took place after the securing of Guadalcanal. This episode (video link at bottom) is one of a series entitled Battle History of the U.S. Marine Corps: Marines in the Pacific.
Courtesy of Wikipedia (most links disabled):
The Battle of the Coconut Grove was a battle between United States Marine Corps and Imperial Japanese Army forces on Bougainville. The battle took place on 13–14 November 1943 during the Bougainville campaign, coming in the wake of a successful landing around Cape Torokina at the start of November, as part of the advance towards Rabaul as part of Operation Cartwheel.
In the days following the landing, several actions were fought around the beachhead at Koromokina Lagoon and along the Piva Trail. As the beachhead was secured, a small reconnaissance party pushed forward and began identifying sites for airfield construction outside the perimeter. In order to allow construction to begin, elements of the 21st Marine Regiment were ordered to clear the Numa Numa Trail. They were subsequently ambushed by a Japanese force and over the course two days a pitched battle was fought. As the Marines brought up reinforcements, the Japanese withdrew. By the end of the fighting, the Marines had gained control of a tactically important intersection of the Numa Numa and East–West Trails. A further action was fought around Piva Forks in the days following the ambush.
In early November, 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. A Japanese counter landing at Koromokina Lagoon was defeated in the days following the US landing, and the beachhead was subsequently secured. Following this, a blocking force was pushed forward towards the Piva Trail, a key avenue of approach towards Cape Torokina, to defend the narrow beachhead while further supplies and reinforcements were landed. The Japanese commander on Bougainville, Lieutenant General Harukichi Hyakutake, ordered the 23rd Infantry Regiment to advance towards Cape Torokina from the main Japanese position around Buin. Heavy fighting subsequently took place during the Battle for Piva Trail as the Japanese advancing from Buin clashed with the Marine blocking force. The battle resulted in the capture of Piva by US forces, after which a small reconnaissance party of naval construction personnel, escorted by a force of Marine infantrymen, was sent out in search of of a site suitable for an airfield. Led by Commander William Painter, a Civil Engineer Corps officer, the party identified a suitable location about 1 mile (1.6 km) beyond the perimeter, about 3 miles (4.8 km) inland, and they set about preparations for the construction of several landing strips for bomber and fighter aircraft.
E04: Bougainville – Securing the Solomons 23 min