During World War II, the Japanese Armed Forces captured nearly 140,000 Allied military personnel (Australia, Canada, Great Britain, India, Netherlands, New Zealand, and the United States) in the Southeast Asia and Pacific areas. They were forced to engage in the hard labour of constructing railways, roads, airfields, etc. to be used by the Japanese Armed Forces in the occupied areas. About 36,000 were transported to the Japanese Mainland to supplement the shortage of the work force, and compelled to work at the coal mines, mines, shipyards, munitions factories, etc. By the time the war was over, a total of more than 30,000 POWs had died from starvation, diseases, and mistreatment both within and outside of the Japanese Mainland.
56,000+ of those held by the Empire of Japan were recorded in the War Departments records now held at Kew under the title ‘BRITISH PRISONERS OF WAR HELD IN JAPAN OR JAPANESE-OCCUPIED TERRITORY’
There is a very extensive research guide here also: https://www.forces-war-records.co.uk/prisoners-of-war-of-the-japanese-1939-1945
Further research guides: https://www.forces-war-records.co.uk/free-tutorials
Please be aware that due to the way we collate, and cross reference our databases, some records will contain more information than that listed above.
Original Source: National Archives reference WO392/23-26