Forced Labor Mobilization of Koreans and Chinese on Hashima Island

Hashima (commonly called Gunkanjima, 'Battleship Island'), off Nagasaki harbour, was an undersea coal mine operated by Mitsubishi. As the war in China widened and Japanese miners became scarce, the group transfer of Korean labourers began in earnest from 1939, successively through 'recruitment', 'official mediation' and, from September 1944, formal conscription; in 1944 about 200 Koreans who had been working in coal mines on Karafuto (Sakhalin) were also reassigned to Hashima. Chinese labourers, including prisoners of war, were brought to the island late in the war; sources give either 1943 or 1944 for their arrival.

From the late 1930s until Japan's surrender in August 1945, these conscripted Korean civilians and Chinese prisoners of war worked in the undersea coal mines. The existing account states that workers endured 12+ hour shifts in shafts up to 600 meters below sea level, extreme heat, inadequate food and water, and brutal physical punishment, and that escape attempts were met with severe reprisals; a 2012 report by a South Korean government commission speaks of workings more than 1 km down, too cramped to stand in, with temperatures above 45°C. Survivors such as Seo Jeong-u and Choe Jang-seop testified to frequent roof falls, rations consisting largely of bean residue, and the beating and torture of men caught trying to escape. The Koreans were housed in barracks on the island, and the Chinese were confined in a fenced compound at its southern tip.

The figures differ by source and need to be attributed separately. For the number of Koreans, the existing account gives approximately 500-800; Takazane Yasunori of the Nagasaki Association to Protect the Human Rights of Koreans in Japan and the South Korean commission both give about 800 (an estimate). The number of Chinese is given as 204. As to deaths, the Nagasaki association obtained in 1986 the island's applications for cremation permits covering 1925 to 1945 (the 'Hashima documents'), and the South Korean commission, working from Japanese records, confirmed 122 Korean deaths; Takazane, citing the researcher Takeuchi Yasuto, gives 48 Korean deaths after forced mobilisation began in 1939 and 15 Chinese deaths. The frequently quoted figure of 137 equals 122 Koreans plus 15 Chinese. Estimates of 'about 1,300' or 'over 1,000' are close to the total number of deaths in the cremation records including Japanese residents, and are not a count of Korean and Chinese deaths. The exact death toll therefore remains disputed.

In 2007 the Nagasaki District Court, in a suit brought by Chinese plaintiffs, recognised the forced transportation and forced labour as unlawful acts while dismissing the compensation claims. The mine closed in January 1974. The forced labor history became an international flashpoint when the island was nominated for UNESCO World Heritage status: at its inscription on 5 July 2015 as part of the 'Sites of Japan's Meiji Industrial Revolution', Japan's representative stated that in the 1940s a large number of Koreans and others had been 'brought against their will and forced to work under harsh conditions' at some of the sites. An Industrial Heritage Information Centre opened to the public in Tokyo in June 2020, but in 2021 the World Heritage Committee found Japan's interpretive measures still insufficient and expressed strong regret.