@Flashman:
If the setup was historically accurate, the Baltic States would be neutral and Bessarabia part of neutral Romania; this would give the Russians something to do R1. Also, Persia should be Pro-Axis giving them something to think about on their southern border.
But I don’t think Soviet units should EVER be allowed to share territory with other Allies. Even when at war ships can share the same sz, but not fight together. Similarly I’d allow US/UK units to land in Russia on NCM, but not defend with them if the tt is attacked. Stalin simply didn’t want to share the glory with anyone else. He’d take your money but he wouldn’t plough your path for you. He didn’t even help the Polish partisans in the Warsaw uprising.
To balance, the same thing should apply to Japan in regard to German and Italian units and tts, as there was practically no military cooperation between Japan and the Euro Axis.
In other words Japan and the USSR should be considered to have allies only in the sense that they have enemies-in-common with other powers. They are still members of the two great alliances for game victory purposes, but are essentially fighting different wars. Some monetary aid to Russia from the West is authentic, but then Germany got huge non-military aid from Russia until it decided to invade the place…
Excellent stuff Flash, and for (at least house rules) easy enough to correct in the game.