Those who can rule the water can also rule the country. This proverb became a reality, especially during the Sengoku period (Warring States Period) in Japan.
Shingen embankment was a flood control system built over 400 years ago to protect the northern part of the Kofu Basin, the rich rice paddy areas of Kai Province, then under the rule of Daimyo (District Lord) Shingen Takeda. The main problem is that the Midai River, a left branch of the Kamanashi River, is the major branch of the Fuji River, Once the Midai River flow increases and broke the bank protecting the Kofu Basin at its confluence with the Kamanashi River, the flood damage to the paddy fields was extensive. Such floods were known even in prehistoric times. Towards AD 1500, Shingen Takeda, the Daimyo (District Lord) of Kai country, directed that flood control works be made to protect the rice paddy area of his country (Takeuchi, 2003*).
Shingen Takeda was one of the strongest Samurai Daimyo (District Lord). He controlled his soldiers well and so did the floods.
Figure: Shingen Embarkment**
*The Basis of Civilization: Water Science? (Proceedings of theUNESCO/IAMS/IWHA symposium held in Rome, December 2003). AI IS I’ubl. 286, 2004
**Brochure (Information about Fuji river Flood Control)