This was the US seizure of Abemama atoll in the Gilbert islands group of the central Pacific Ocean (20/23 November 1943).
The atoll officially named Abemama and codenamed 'Boxcloth', later changed to 'Bumpkin', was generally called Apamama in almost all US documents during the war.
Abemama is located in the centre of the Gilbert islands' chain about 75 miles (120 km) to the south-east of Tarawa atoll. Many of its islands/islets did not have names, and in history are now generally identified by their codenames. The oval-shaped Apamama atoll is 15 miles (24 km) long on its north-west/south-east main axis and 6 miles (9.6 km) wide with an area of 10.57 sq miles (27.37 km˛). The lagoon provides a deep and well-protected anchorage. The ends of the atoll and its north-eastern side is bordered by six islands and islets. The largest is the main island of Apamama, which is hook-shaped, about 7 miles (11.25 km) long and between 1,000 and 2,000 yards (915 and 1830 m) wide, and a mere 12 ft (3.6 m) above sea level. It occupies most of the north-eastern side to the lagoon and hooks around its north-western end. Off its south-eastern end is the next largest island, Otto, and between the two is the islet Oscar. On the south-eastern end of the lagoon is the third largest island, the crescent-shaped John, with the islet of Orson between it and Otto, while Joe, another islet, lies off its western end. From Joe islet’s western end a submerged coral reef runs to the north-west to Entrance islet. The main access to the lagoon is the South Passage, which runs to the north-west of Entrance. Another submerged coral reef continues to the north-west as far as Abatiku island, then hooks to the north-east connecting with Apamama Island. A secondary entrance, the Western Passage, lies between Abatiku and Apamama islands. All of the gaps between the islands and islets between Apamama and Joe can be forded without difficulty at low tide.
The islands are covered with coconut palms and salt brush. Almost 1,000 persons lived on the atoll in several villages, and Tabontebike was the government station.
The Japanese first occupied Apamama on 31 August 1942 using a small special naval landing force detachment from Jaluit. This force departed on 4 September, and an element of 6th Special Naval Landing Force reoccupied the island on 20 November. In February 1943 the 6th Special Naval Landing Force was redesignated as the 3rd Special Base Force and the detachment garrisoning Apamama then came under the command of the Gilberts Area Defence Force.
In the middle part of October 1943 the atoll appeared to be unoccupied by the Japanese, and the V Amphibious Corps Reconnaissance Company was given the task of reconnoitring Apamama to establish whether or not it was occupied. If occupied in strength, elements of the 6th Marines were to assault the atoll on 26 November 1943. Loaded aboard the submarine Nautilus, the 68 marines and 10 engineers of the company travelled first to Tarawa and then to Apamama. The submarine was errantly attacked and damaged by a US destroyer while on its way, but was able to proceed and arrived off Apamama during the afternoon of 20 November. The company landed by rubber boat on the western side of Joe at 04.45 on the following morning: it had intended to land on Joh just to the east, but the current swept the company slightly to the west. The company then moved across John, in the process engaging a Japanese patrol. As they approached from Orson on 23 November, the marines found 23 Japanese entrenched on the southern end of Otto, tried to withdraw and attempt to outflank the strongpoint by rubber boat, but was pinned down. Nautilus shelled the strongpoint and on the morning of the next day the marines found that all of the defenders who had not been killed by the shelling had committed suicide.
The marine losses were two killed and two wounded.
Two days later, on 25 November, the 3/6th Marines arrived in the transports Harris and President Monroe to occupy the atoll, and was quickly reinforced by the 8th Marine Defense Battalion. The building of O’Hare Field as a bomber facility was soon begun by a force of 95 'Seabee' construction troops, and this was completed on 17 December with a 7,000-ft (2135-m) runway on the north-western hooked end of Apamama island, and this airfield became operational on 15 January 1944. The facility was supplied by the dredging of a channel, wide enough to two tank landing ships, through the reef.