I’m catching up on the forum activity after having been out of town for a couple of days, so I’m commenting on this thread a bit late. Amanntai explained that his proposal was originally a joke, but that he’s subsequently made an actual three-side setup – so for whatever it’s worth, here are a few thoughts on the subject.
The notion of having the USSR basically fighting its own war does a have a certain degree of historical basis, in the sense that the Allies were fighting what could be called simultaneous semi-independent wars: the British (plus Commonwealth) and the Americans on the Western and Mediterranean/North African fronts, the Soviets on the Eastern Front, the Americans in the Central Pacific, and the Americans and the British (plus Commonwealth) in the Southwest Pacific and in the China-Burma-India theatre (with the Chinese, of course, fighting in China itself). Moreover, there was also a lot of mistrust and competing agendas between the Soviets on one side and the Anglo-Americans on the other side, and these differences took center stage when WWII ended and the Cold War began.
For that matter, the Axis powers were themselves fighting two largely independent wars: one in the Asia-Pacific region and one in Europe and its periphery. The fact that Japan was able to carry on with its war (though admittedly only for three months) after the Axis surrender in Europe illustrates that the Japanese and European Axis war efforts were largely independent in their aims and their means. There was little military coordination between Japan and the European Axis nations, a situation not helped by the fact that it was virtually impossible for them to send assistance to each other in the way that the British and Americans and (to a letter extent) the Soviets could do.
All in all, my feeling is that it would be a bit more realistic for a “three-sided” A&A game to consist of the Allies, Germany and Japan rather than the Axis, the Anglo-Americans and the Soviets, in the sense that the Axis war effort was less coordinated and less inter-dependent than the Allied war effort. Assuming for the sake of argument, however, that the second of those three-sided models was being developed into a house rule, I’ll just comment on Amanntai’s idea that all strict neutrals would be considered pro-Russia instead of strict neutral, and Black Elk’s idea of bringing the Chinese Communists into the equation. Regarding the neutrals, my recommendation would be to treat the six territories constituting Mongolia as being pro-Soviet (which they definitely were in real life) and to leave the other neutrals unchanged (since none of them, to my knowledge, were pro-Soviet). As for China, my suggestion would be to treat only Shensi as a ChiCom territory. Shensi is roughly where Mao’s Communists ended up after the Long March, and it’s the Chinese territory which, as far as I know, would have best qualified as being considered “Communist controlled” during WWII. I’ve attached below a close-up of part of my customized Global 1940 table, whose default roundels illustrate these elements, in case it’s useful.