National Advantages. NA’s. They are optional rules in the OOB rule book that give a different ability to certain units or make an exception to certain rules depending on the country. I haven’t really played with them but it is said that they add some variety to the game.
Looking at the map and the way the territories are laid out, I think there are some very cool things Russia can do if they are forced to fall back to Cauc and Mos.
Or, if you are like me, just raid chips (and extra Japan INF and ARM, something else I have run out of in the last 2 games I played) from your Milton Bradley Classic AA game. Exactly the same size and style :-)