Sgteasy, according to real history, Japan really started pushing south in 41-42. So in all actuality, you're pretty much obligated to be invaded.

Granted they will be in for a surprise when they get there and discover there's more than just a few us bases and stretches of undefended oceania. 

With that said, Japan may fare a little better if china is a solid nation due to not wasting troops fighting the British in Hong Kong etc. But it depends on how it plays out.

A Japan player would be nice but sadly it would change my intended pacific theatre plotline due to not knowing where the war will ultimately end. 

Regardless as to if clock tower takes Japan, this is shaping up to be interesting. I just hope the European theatre lights up soon.