Once you have the ball rolling on Japan, Tokyo is far easier to capture, than if you had the ball rolling on Germany and tried to capture Berlin.
Getting the ball rolling on Germany is easier and more profitable, but actually capturing Germany is a pain.
Generally, I will contain Germany first with all 3 Allies, then switch off to holding off Germany with UK/US transports from W. Canada, and then use Russia and US to actually kill Japan. Usually the Axis player will resign around the point I kill the majority of Japan’s forces in Asia, because it’s evident the Axis can’t possibly take Russia, and Allied reinforcements are growing every turn.
That is, of course, if the Allies are winning, which is usualy for me.