Japanese submarine secrecy and treaty evasion

Japan's geography and ability to restrict access to naval yards made clandestine submarine construction easier to conceal than in Britain, the United States, Australia, or Germany. Covered building spaces, maintenance access, movable boats, and alterable hull numbers could complicate outside counting. More systematic concealment becomes a missed opportunity only if Japan was prepared to cheat the treaty system. The discussion immediately broadens the criticism because other powers also manipulated treaty wording, obeyed the letter while violating the spirit, or sometimes ignored both. The point is weak enforceability across the system rather than uniquely Japanese bad faith.