Tamagawa Canal is one of six Edo canals built in 1653 by Ina Tadaharu. The operation was handled by Tamagawa Brothers (the name of Tamagawa was given after the completion of the canal). Because the altitude difference between Hamura and Yotsuya(Shinjuku) was 100m, the constuction was very difficult. Hamura Brothers had to sale their house to finish the job because they spend all the budget from the government. In 1654, they finished the construction.
After the work, they were given Tamagawa name and assigned as the director of the security guard of Tamagawa water.
There is the ruins of the house next to the dam.