Deterrence worked because foreign powers knew the fleet's strength

Many Six-Six Fleet ships were ordered from British and French yards, so potential opponents knew their capabilities and observed Japanese crews training. That transparency strengthened deterrence by making clear that victory might require sixteen to twenty-four large warships. A prospective attacker then had to ask whether it could assemble that force without neglecting other global commitments. Losing the first battle would be especially damaging for a great power because the follow-up campaign would need to be larger and visibly decisive. By contrast, late-1930s Japanese planners tried to combine deterrent power with secrecy about their strongest ships.