The Korean War was a huge benefit to Japan and was a great help to the Japanese economy. In fact, South Korea studied how Japan was able to use the Korean War to help their nation's recovery in order to replicate the same success in the Vietnam War.The Japanese played a minor part in Japan. They loaded and unloaded ships/planes. They continue to sweep Japanese waters for old minefields (the last units of the Imperial Japanese Navy were employed until 1950 on that duty). Basically, they were the dog's bodies which did all the labour in and around US units in Japan.