The supplier network and aircraft production in wartime Japan

The Japanese aircraft industry, which was very small scale before the Second World War, became Japan’s largest manufacturing industry by the end of the war. This article explores the basis for the growth of the aircraft industry during this time by focusing on Mitsubishi Heavy Industries Company’s No. 5 Works. It was revealed that during the war, the supply of basic inputs increased substantially: labour force, equipment, and ‘machinery parts’ were in sufficient supply and none of these was a binding constraint on production. The binding constraint existed in the supply of ‘special parts’. In other words, aircraft production expanded as the supply of special parts increased. This increase in the supply of special parts and still faster growth in the supply of machinery parts came about through the expansion of the supplier network in terms of both the number of suppliers and the geographical area in which they were located. These findings imply that outsourcing played a key role in the growth of aircraft production in wartime Japan.