The All Japan Dockworkers' Union (JDU; Japanese: 全日本港湾労働組合, Zenkowan) is a trade union representing port workers in Japan.
The union was established in 1946, and was affiliated with Sanbetsu.
[1] However, in 1950 it switched to the new General Council of Trade Unions of Japan (Sohyo).
[2] Its membership reached 28,214 by 1970,[3] then fell to 22,124 in 1985.
In 1989, Sohyo merged with the Japanese Trade Union Confederation, but Zenkowan instead opted to become independent.