ORIGINAL: brian brian
I think Russia can always afford to leave a couple-three, (and NO more) cheap units (and more importantly, slow - the slow ones aren't much use in a 41 Barb) behind in the Pacific, and make Japan earn it's rewards somewhat. The US will thank you at least. I'm not saying Russia should overcommit in Asia, that is a classic mistake that has lost the Allies many a game of WiF. But I don't see any point at all in surrendering...depending on the situation in the Middle East, that has too many angles to be a cut and dried decision. Besides, if you surrender, it might be a pain in the butt to re-DOW Japan later in the war when you want to. And there is too much fun to be had with the 2-5 Cavalry that can't fight the Germans anyway. Japan just doesn't have the logistics support to deal with land campaigns over large areas like Siberia.
I also like to use the Japanese ATR (or more likely the Flying-Boat NAV/ATR) to fly the MTN corps to the lake in NW Manchuria for a surprise drive on Chita.
In the case of a 1941 barb combined with a determined Japanese attack on the USSR at the same time, if you only leave 2-3 units in Asia and Japan attacks in force, you have to expect to loose at least Chita, and possibly have Japan pressing on all the way to Irkutsk in 1941. While that's not the end of the world, it's definitely worse than surrendering all hexes on the Pacific map (which you will lose anyway). Especially if you can keep that resource SE of Chita, it's much better. We find that this situation is quite common in our game, since we typically see China being conquered some time in 1941 or 1942, which frees up enough Japanese ground units to attack both the USSR and the allies.
If China is still strong, and Japan is setting up for attacking the allies in strength, Japan will often not have the musscle to send a strong force into Russia. In this case, it may be ok to try to make a stand. (3-6 japanese land units can of course be stopped by 2-3 russian defenders). But if Japan attacks Russia with 10-20 units, Russia will either have to set up 6-10 units in defense, or at least face losing Chita. And 6-10 extra units vs Germany can really make a difference.