Xibei San Ma
Mongolia - the most annoying, or amusing, nation in the game. You have a few provinces, 6 IC, and are a puppet of the Soviet Union. Not bad? Then go on.
The first years
Now. You MUST declare war on Sinkiang as soon as you get the troops on the border. Don't mind the dissent hit. You won't be the one waging the way anyway. Who will it be then? Look up. Or, in other words, look north. Yes. That red blob is gonna help you. You just have to get to wait a week or so to get help. Nationalist China may DOW you at the moment, but don't mind that. Just bunker on the borders and let the Soviets do everything for you.
The wars should be all done by now. And you should annex the last warlord (For me it was Shanxi, but stuff like that varies) Japan should kick in 1938 too and go landgrab on it. Halt them AS FAST AS POSSIBLE. If you fail, you'll probably lose the most valuable provinces - Nanking and most of the coast at all. If you do this perfectly, you get 80 IC on full IC takeover. Without it, just 16. Will do anyways.
1940 - 1944
You should build up in these years. SU will be at war with Germany already, but don't mind that, they will survive. If they don't, well, reset the game.
Now it's the time for your great showtime. Declare war on Japan. By now, you are meant to have an army at least the half of Japan's. Germany should be done with too, so the SU has a lot of free troops to help. If you need them or not, you decide, but they will show up anyway.
Your hand is free now. You hae established a great empire in Asia, taking over China and going at it with Japan. Remember - go for Tokyo before the Americans do it, if you didn't already. That's a hole full of IC, I can say. Genghis Khan would be proud of you.