As the beachhead was secured, a small reconnaissance party pushed forward and began identifying sites for airfield construction outside the perimeter.

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.

[2] 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.

[4] Heavy fighting subsequently took place during the Battle for Piva Trail as the Japanese advancing from Buin clashed with the Marine blocking force.

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,[5] and they set about preparations for the construction of several landing strips for bomber and fighter aircraft.

As a result, it was initially impossible for US forces to advance the perimeter of their beachhead far enough to cover the proposed airfield site selected by Painter.

[8] As these preparations were taking place, the Japanese, unbeknownst to the US commanders, had occupied a strong position around the coconut grove.

[5] Throughout the night of 12/13 November, the Marines' orders were modified to increase the size of the patrol to two companies, with a headquarters element and an artillery forward observer team to control fire support.

They were to move to an assembly area positioned to the rear of the front line held by the 9th Marine Regiment and wait for the rest of the battalion to arrive before continuing.

It was reported by the gunnery sergeant that Rapp had found it increasingly difficult to control his company, suffering some casualties and platoons intermingling and becoming disorganized.

At 18:30, communications were reestablished, and artillery was ordered establish pre-designated fire zones north, east, and west sides of the 2nd Battalion, 21st Marines' perimeter.

Ames ordered Smoak to send out patrols and prepare to attack the Japanese positions in the morning with tank, artillery, and aircraft support.

[14] Throughout the night the Japanese defenders fired their rifles sporadically but made no attempt to assault the Marine positions.

At 09:05 airstrikes were called in, with 18 TBF Avengers from VMTB-143 bombing and strafing the area after artillery marked the target with smoke.

Japanese fire having stopped, all companies were directed to stand fast in the positions where they found themselves and to send out patrols to a distance 100 yd (91 m) north of the trail junction.

Riflemen with grenades quickly dealt with these, and by 14:00 all Japanese resistance had been overcome and patrols returned, reporting no further contact.

[20] Although not provided for in the first phase of the battle when Company E advanced up the trail,[22] artillery preparation was later recognized as of prime importance against the Japanese system of defenses, with their well dug-in, concealed, and covered foxholes, equipped with a high percentage of automatic weapons, in turn covered by riflemen in trees and spider-holes.

[20] This enabled construction of the Piva airfields to begin; meanwhile, further supplies were landed around Cape Torokina as the beachhead was further consolidated.

[24] A few days after the fighting around the Coconut Grove, the Battle of Piva Forks, the final major action around the Torokina beachhead for 1943, was fought.

[25] While minor actions were also fought around Hellzapoppin Ridge and Hill 600A in December,[26] the fighting around Bougainville largely died down until March 1944 when the Japanese launched a large-scale assault on Torokina.