Russia can send troops into China in order to disrupt Japan.
Even Cow do not declear war on allies r1 with Japan if Russia support China.
I do not claim this is optimal play, but against a weak or unlucky German r1 (or mabye against a strong Japan player) its a good move.
Here is how you do it:
- Buy 1-3mec, the rest inf and art
- DOW Japan
- Send starting mec and tnk to Sikang and Kazakhstan
- Fly planes to Suiyuyan
from there they can attack Amur, Chahar and Yunnan, or simply fly back to Moscow or Caucasus.
- Place mec in Stalingrad
You may actually retreat far east USSR units towards Moscow… Depends on your strategy
R2 move the units to Yunnan or Shensi.
Collect your China NO r2?
Send Stalingrad mec to China
Now China may can-open for your mobile USSR troops so that they may target stacks that would normaly be safe. This creates all kinds of different headaches for Japan.
Unbalance solid Japan player
Protect India and China
You may send the troops back to Russia, if you need to
BEWARE: All USSR units away from the motherland is an invite to Germany rush!
Greater need for allied help in Moscow.