Chris: "How accurate is it to describe imperial Japan as fascist?"
Not, very, in my opinion - though I guess a lot depends on your definition of Fascism. Mine (following Trotsky's, I think) would turn on the mobilisation of a mass petit bourgeois movement to take on the workers' movement.
On that score, Japanese militarism is a long way off Fascism.The working class and the left in Japan was far from being as combative as it was in Germany or Italy. The militarisation of society was thorough, but I don't believe that the military was supplemented by a mass fascist movement in the way it was in the other Axis countries.
The Sanpo movement of workers' discipline arose out of a shrunken labour movement, before its incorporation into the state. The initiative coming from labour leaders is closer to the British experience of Joint Production Committees than the Nazi Labour Front (though the British labour movement had greater authority over more workers).
As far as I understand it, it was an important component of Japanese Communist Party doctrine that the military leaders in Japan were Fascist, but that is because of the needs of Soviet Communist doctrine, i.e. that after 1941 the world was divided between the camp of democracy and the camp of Fascism. Jon Halliday, in his book on Japanese Capitalism, written when he was a New Left Review EB member, dismisses the argument that it was a Fascist state.
Certainly Japan was imperialist, though it was unlike the other imperialist powers in that they did not accept its membership of the imperial club. That probably shaped the ideological projection of Japanese imperialism as a Greater Asian Co Prosperity Sphere - not always very convincing, especially in China. On the other hand Subhas Chandra Bose's Indian National Army did fight alongside the Japanese when they let him, and nationalists in Burma and Indonesia were impressed by the defeats that the Japanese inflicted upon the British and other white imperialist powers.
When Asians did take on the Japanese occupation, as in Korea, Vietnam, Malaysia, and Burma they got precious little thanks for it from the allies, who quickly dismantled their ad hoc committees of national liberation, and in Indonesia and Korea released the same Japanese military police who had been in charge before to act as deputies for the allied occupation.