This is a famous historical case in Japan that pitted two unequal forces against each other: the Furukawa Corporation and peasant protesters. Prior to the Ashio mining activities before 1880, the surrounding area was densely forested. The destruction of the trees caused by the concentrated sulphurous acid from the mines, caused the erosion of the topsoil, which allowed the rainwater to flow directly into the river. As a result, the Watarase River carried the poisons and affected the agricultural lands nearby. To further worsen the problem, the Ashio mine lacked storage facilities for the slag and untreated ores. Thus, these materials accumulated in the rice-fields through the irrigation systems and caused the topsoil to turn hard like cement. As the copper mining continued, damage to the agricultural lands increased, the farmers were forced to close the irrigation canal gates to keep out the poisons every time it rained. The poisons also affected the quality of drinking waters, which had a serious affect on the people’s health.