The technology of constructing a fortress island in the sea at a depth of 8 to 12 meters without using a machine was unique in the world.
Due to large-scale earthquakes such as the Tokyo Metropolitan Earthquake and the Tokai-Tonankai-Nankai Earthquake, it was… 
Although there are no brick constructions such as barracks, bunkers and concrete constructions such as batteries… 
Foot wall and back wall of upper part installation of No.2 Sea Fort were made of… 
Revetment work also adopted for construction of the No.3 Sea Fort. No.2 Sea Fort was the artificial… 
From No.2 Sea Fort they found some other bricks other than Oukashourenga (brick with cherry seal)… 
Akinori Nishida was born in Iwakuni (Yamaguchi Prefecture). At the end of the Edo period, it… 
Many workers, not just engineers, engaged in the construction of the sea fort. The "Memorial to… 
Akinori Nishida contributed in technical aspect of Tokyo Bay Sea Forts construction plan. He collected documents… 
Construction of No.2 Sea Fort relied on human power It is said that the construction of…