 Because of its late discovery the historical role of the coalfield could not be compared with that of the Chikuho coalfield, but its economic importance since the Japanese industrial revolution is comparable with that of the southern Chikuhō coalfield.It was explorer Matsuura Takeshirō (松 浦 武 四郎), who, during his journey through Hokkaido in 1857, first marked the coal seams on the banks of the Sorachi river near Akabira.In 1868, carpenter Kimura Kichitarō (木村 吉太郎) discovered coal in Horonai, Mikasa (三 笠).