Significant technology of the No.2 Sea Fort construction.

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.

Bricks construction and bunker

Marks on bricks

brick with cherry engraving From No.2 Sea Fort they found some other bricks other than Oukashourenga (brick with cherry seal)…
Technology of the No.2 Sea Fort construction

Construction schedule table

Construction Akinori Nishida contributed in technical aspect of Tokyo Bay Sea Forts construction plan. He collected documents…