Tragedy of Toyama prefecture

More than 1000 years ago in central Japan local miners began to extract precious metals. During the centuries gold, lead, silver, and copper were extracting from the Kamioka mine of Toyama Prefecture.

In 1904-1905, the Russo-Japanese War broke out; another 10 years later, Japan entered the First World War. The country badly needed metals, especially in zinc - for making armor, aircraft, and ammunition. Approximately at this time, as early as the 1910s, first cases of an unknown disease were recorded, which affected local peasants who came to the doctor and complained of severe pain in the bones and joints.