In 1945 World War II ended, and there were no longer controls on speeches and meetings, and in the following year, the peasants of the Watarase-gawa valley of the eastern Gunma Prefecture gathered and formed the Union for Relocation of Ashio copper mine Refinery.
1945年、終戦となり、言論・集会への弾圧が行われなくなると、翌1946年、群馬県東部の渡良瀬川流域の農民が集まり、足尾銅山精錬所移転期成同盟会が結成された。