Construction began in 1967, with effective completion in October 2019[1] and the official opening on 1 April 2020.
The dam's construction had seen sustained local opposition and a ballooning budget, and a change of National government in 2009 resulted in the project being halted, being about 70% completed at the time.
Construction required the relocation of part of the Agatsuma Line, several roads and affected residents.
[1] Yamba Power Plant, an 11,700 kW hydroelectric station attached to the dam, began operation on 1 April 2021.
This article about a dam or floodgate in Kantō region of Honshu, Japan is a stub.