Robert Farley
In January 1936 Japan announced its intention to withdraw from the London Naval Treaty, accusing both the United States and the United Kingdom of negotiating in bad faith. The Japanese sought formal equality in naval construction limits, something that the Western powers would not give. In the wake of this withdrawal, Japanese battleship architects threw themselves into the design of new vessels. The first class to emerge were the 18.1-inch-gun-carrying Yamatos, the largest battleships ever constructed
http://nationalinterest.org/blog/1942-japan-ordered-two-battleships-be-built-huge-23-inch-22939