In October 1934, under great security, the Japanese Navy started plans for a super battleship, and 22 months later a proposal called A140-F5 was adopted. In 1929-30 just when the restrictions were coming to an end, the Treaty of London was signed, which imposed similar restrictions on the nations of the world as far as ship building was concerned. During this time, Japan constructed four of the eight planned ships Nagato, Mutsu and the Akagi and Kaga which were converted to aircraft carriers, so that the grand plan of 8-8 was not carried out. In 1921, most of the major nations, including Japan, signed the Treaty of Washington, which limited the total number and tonnage of capital ships for a ten year period.

In addition to these 16 capital ships, 4 huge leviathans armed with 46cm guns and a displacement of 47,500 tons were to be built. This concept was to include 8 new battleships and 8 new battle cruisers.

Just prior to the conclusion of WWI, the Japanese Navy was considering to modernize their aging fleet with a very strong and powerful line of new warships, called the Eight-Eight squadron.

World of warships ijn musashi