Pearl Harbor fell short of Japan's decisive-battle doctrine

Nagano is assessed as a better admiral than Dönitz, but Japan demanded a far greater strategic result from him. Kantai kessen doctrine expected a battle that would destroy the United States Navy and force a political collapse. If Pearl Harbor was meant to serve that purpose, Nagano and Yamamoto needed to concentrate as many carriers and aircraft as possible, provide more fuel, and continue attacks against shipping and infrastructure. The comparison with Taranto and Copenhagen makes the standard explicit: a truly decisive strike removes the enemy fleet's capacity to act. Pearl Harbor inflicted a shock but did not deliver the strategic annihilation Japanese doctrine required.