We've explored a Nazi victory in WW2 a fair bit, but what about a Japan that dodges the war?
Say Chiang bites it in 1937, and China relapses into warlordism. Japan continues to industrialize Manchuria, meddle in northern China, but it doesn't feel the need to strike south; there's no US oil embargo, because there's been no war in China and moves south (which were pushed by the invasion of China).
By 1943, Japan realizes that not going to war is a wise idea.
So, it's 1945. The Japanese still rule Manchukuo, Korea, and have puppeted Northern China. The Soviets and Americans, meanwhile...