Kudos to Mike (Warhorse)!

[berto]

During the initial scenario development phase, I discovered that both the Japanese and the Soviet Union OOBs were labeled as "Axis" - making it impossible for them to be combatants.

From the code:

---

case XRussiaNation :
...
return XAlliedSide;

...

case XSovietNation :
...
return XAxisSide;

---

You couldn't have used the Russian (not the Soviet) OOB?

BTW, in future releases, we are looking maybe to give modders complete freedom to assign "Axis" vs. "Allied" sidedness at will.