The Ashio Copper Mine (足尾銅山, Ashio Dōzan) was a copper mine located in the town of Ashio, Tochigi, (now part of the city of Nikkō, Tochigi), in the northern Kantō region of Japan. It was significant as the site of Japan's first major pollution disaster in the 1880s and the scene of the 1907 miners riots. The pollution disaster led to the birth of the Japanese environmental movement and the 1897 Third Mine Pollution Prevention Order. The pollution incident also triggered changes in the mine's operations that played a role in the 1907 riots, which became part of a string of mining disputes in 1907. During World War II the mine was worked by POW forced labour.