The 20-day-long Korean strike against the Asō coal mines in 1932 was the only sustained strike by a large number of Korean miners in prewar Japan and the largest strike of the year in Chikuhō, Japan's most important coal field. The 400 strikers demonstrated courage and cohesion but won at best a partial victory that left most of them without jobs. This article draws on union documents and a contemporary report by the Kyōchōkai, a semiprivate organization devoted to labor-capital harmony, to explore the background of the strike, the tactics employed by the male strikers and their wives, and the many obstacles they faced in their fight for better wages and working conditions. The author argues that there was little the workers could do to overcome the harsh anti-union environment of prewar Japan or the surpluses in both coal and labor brought on by the Great Depression, but that the strike might have been more successful if rank-and-file Japanese miners had shown even a hint of solidarity. While a Japanese mining union provided organizational support, the failure of even one Japanese miner to join the strike suggests that Japanese working-class racism severely limited the potential for joint Korean-Japanese action.