This is a surprisingly difficult question. Forced labor was endemic among POWs in Japan, yes. But for the most part the most horrifying uses of POW forced labor were primarily relegated to the Burma Railway (the subject of the movie Bridge of the River Kwai, which although fictional captured the feel of the railway) as well as various projects in the Dutch East Indies and China. There is also the Koain, a Japanese government agency, that was used to round up a large number of Chinese laborers for forced labor in East Asia, including mining and war industries. At least some Chinese laborers were forced to work for the Manchurian Industrial Company, which was a joint venture with the original Nissan conglomerate, or zaibatsu.

The thing with the Japanese zaibatsu is that many of their leaders were actually opposed to a war with the West-namely, it was bad for profits. In fact, one of the contributing factors to the rise of Japanese militarism was the assassination of a prominent zaibatsu president, Yasuda Zenjiro. Partly due to this opposition, a large number of Japanese industries were nationalized by the government, making it questionable as to whether or not a Japanese company was responsible as opposed to the government itself. On the other hand, most of these zaibatsu benefited from the war as it gave the shipyards and aircraft manufacturers a significant amount of product.