Koma

Koma was a district of Kai whose riverine settlements depended on managing the Kamanashi and Midai rivers on the western side of the Kofu basin. The flood-control works associated with Takeda Shingen provide a concrete sixteenth-century landmark. The works began after the great floods of 1542, and a document granting exemption from household taxation dates their completion to around 1560. The system was not simply one embankment: stone projections, divided flows and defences at the river junction helped protect settlements and cultivated land. During the Edo period these works were regarded as models of the Koshu approach to river management. A surviving plan was drawn in 1824 to record the embankment’s extent. It preserves evidence of the late Edo arrangement before later reconstruction changed its shape.