@optiso
"I would think they would be saving all their explosive munitions and just using small firearms instead. Oil means they can produce napalm but doesn't real Japan import almost everything?"
Japan is a country, with a country's resources. Munitions can always be made again. Everything the JSDF uses is made in Japan, from the bullets to the rifles, to the tanks, missiles and fighter jets. Even nuclear weapons. The only reason they don't build nuclear weapons is because of treaty obligations. Only using small arms puts the soldiers using them in unnecessary danger. Soldiers are resources too. It's probably the hardest resource for the JSDF to replenish.
Japan imports a lot of things, like oil, but they don't need to rely on it as heavily as they do now. They just refuse to rely on nuclear power, which they do have the technology and infrastructure to build. They can be self-sufficient on food, if they ration. But people gotta live their lifestyle.