1940 September - The village of Horonobe is separated into the villages of Horonobe and Toyotomi 1947 - Mitsubishi Materials begins coal-mining operations in the Toyotomi-Horonobe area.
1940 September - Desa Horonobe dipisah menjadi desa Horonobe dan Toyotomi 1947 - Mitsubishi Materials memulai operasi penambangan batubara di daerah Toyotomi-Horonobe.