1956: Discovery of Minamata disease

1959: Kumamoto University announces its organic mercury theory; Fisherfolks' agitation; Hosokawa feeds cats with the waste effluent from Chisso's acetaldehyde production unit and induces Minamata disease symptoms in them; the factory effluent theory is termed a fabrication by labour unions and the Chamber of Commerce

1965: Discovery of the second outbreak in Niigata

1967: Civil court action by Niigata victims

1968: Government confirms the cause-and-effect relationship between mercury and the Minamata disease

1969: Civil court action by Minamata victims

1971: Victory in Niigata case; wider diagnosis; rapid increase in numbers of reported patients

1973: Civil court victory in Minamata case

1990: Reconciliation proposal in primary court

1993: Reconciliation proposal in higher court

1995: Murayama apologises; reconciliation process starts