page_title: Battle of the Coconut Grove
section_title: Background
hierarchical_section_title: Battle of the Coconut Grove / Background
caption_attribution_description: English: Map showing location of Bougainville relative to New Guinea, New Britain and New Ireland, also indicating political division of Territories c. 1942. Green Islands and Choiseul I. are indicated, also towns of Rabaul and Port Moresby. The land is indicated in white, grey and black, while the sea is a lovely blue. The Solomon Sea, Bismarck Sea and Coral Sea are indicated. The name of Bougainville is highlighted in red.
context_page_description: 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. 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.
context_section_description: 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 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.
  On 9 November, Painter returned to the main perimeter and the following day the combat patrol also returned, having clashed with a Japanese patrol. Further patrols were sent up the Piva Trail, advancing past a coconut grove that was near the intersection with the East–West Trail. These patrols failed to locate the Japanese. The swamps in the area impeded supply and slowed movement. 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. It was therefore decided to establish a strong outpost, capable of sustaining itself until the lines could be advanced to include it, at the junction of the Numa Numa and East–West Trails. This outpost would then be used to send out patrols to disrupt Japanese forces in the local area. On the afternoon of 12 November, General Allen H. Turnage—commander of the 3rd Marine Division—directed the 21st Marine Regiment to send a company-sized patrol up the Numa Numa Trail. The company selected for the patrol was Company E, under Captain Sidney Altman.The patrol was to move up the Numa Numa Trail to its junction with the East–West Trail. From there, the company was to reconnoiter each trail for a distance of about 1,000 yd (910 m), to eventually set up an outpost in the area. As these preparations were taking place, the Japanese, unbeknownst to the US commanders, had occupied a strong position around the coconut grove.
  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. It was also decided to expedite the establishment of the outpost at the junction of the East–West and Numa Numa Trails. In view of the importance of his assignment, Colonel Evans Ames—commander of the 21st Marines—sought divisional orders to send the entire 2nd Battalion, under the command of Lieutenant Colonel Eustace Smoak. This request was subsequently granted, thus enabling the US commander to maintain a company in reserve. Orders were issued for the patrol to step off early on 13 November, with Company E leading out at 06:30. 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.
caption: Bougainville and surrounds
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