Played 5 turns today (long loading times).
I think that Japan not being able to build Tanks is a good descion

Forces me to look towards the Dutch East Indies! Though there is some oil near Chunking I have my eye on....
Anyways -
Ai turn 1 - 2 Northern Spanish cities razed, don't know who by. Spain declares war on Germany.
Ai turn 3 - Germany destroys Poland, Italy destroys Yugoslavia. They captured the cities, no razing.
As for me Japanese forces, well by turn 5 I have taken 2 Chinese cities (Canton and Foochow.......sorry I think I spelling that wrong) and lost alot of my Naval forces to the Americans, though in return I have sunk a load of their subs and destroyers.
Alll in all, I say that playing as Japan is turning out to very fun

And quite difficult as you said Rocoteh! I am enjoying the challenge.