British Commonwealth Occupation Force

The British Commonwealth Occupation Force (BCOF), was the name of the joint Australian, British, Indian and New Zealand military forces in occupied Japan, from 21 February 1946 until the end of occupation in 1952. At its peak, BCOF comprised about 40,000 personnel, equal to about 25% of the number of US military personnel in Japan.

While US forces were responsible for military government, BCOF was responsible for supervising demilitarisation and the disposal of Japan's war industries. BCOF was also responsible for occupation of the western prefectures of Shimane, Yamaguchi, Tottori, Okayama, Hiroshima and Shikoku Island. They were also supported by the Women's Auxiliary Service (Burma). BCOF headquarters was at Kure.

For most of the occupation period Australia contributed the majority of the BCOF's personnel. The initial BCOF presence included the Australian 34th Brigade, the 9th Brigade, 2nd New Zealand Expeditionary Force (J Force), and BRINDIV, a British/Indian division of two brigade groups, the British 5th Infantry Brigade Group (from 2nd Infantry Division in India), and the 268th Indian Infantry Brigade. Major General David Cowan commanded BRINJAP Division from 1945 to 1947. The position of commanding officer was always filled by Australians: Lt Gen. John Northcott, February to June 1946; Lt Gen. Horace Robertson, June 1946 to November 1951, and; Lt Gen. William Bridgeford from November 1951 until the end of the occupation. The British Pacific Fleet initially provided most of the naval forces. The air contingent, known as BCAIR, initially comprised the Royal Australian Air Force No. 81 Fighter Wing, flying P-51 Mustangs, four Spitfire squadrons (including No. 11 and No. 17 of the Royal Air Force and No. 4 of the Indian Air Force), and No. 14 squadron of the Royal New Zealand Air Force flying F4U Corsair.

During 1947, the BCOF began to wind down its presence in Japan. However, BCOF bases provided staging posts for Commonwealth forces deployed to the Korean War, from 1949 onwards. BCOF was effectively wound-up in 1951, as control of Commonwealth forces in Japan was transferred to British Commonwealth Forces Korea.