The 1939 air balance before Japan's later fighters

Hurricanes, P-36 Hawks, Gladiators, Sea Gladiators, and other available Allied fighters would face a far less developed Japanese air arm in 1939 than in 1941. The comparison centres on Mitsubishi A5M and Nakajima A4N naval fighters and the army's biplane Kawasaki Ki-10, rather than the later Zero. The Hurricane is judged clearly superior to the A5M, while the Gladiator is less dominant but still competitive. Japan's later aircraft benefited from two more years of development before the wider Pacific War. War could accelerate research while also forcing services to continue producing designs already available. The 1939 balance looks very different once hindsight from 1941 is removed.