It's a reference to the board game Risk.

The reference is because one of the areas of the game is the Russia/Asia continent, which if you can occupy for an entire turn, you receive seven extra soldiers at the beginning of the next turn. This is the most rewarding continent to hold, as North America and Europe both give five soldiers, and the other areas give less.

However, due to the geographic nature, the Asian continent is extremely open and difficult to hold. The borders are too long and it is too easy for someone in Africa, Europe, Oceania, or North America to get in and take one of the member countries, thus removing your bonus.

Historically, both Napoleon and Hitler attacked Russia in the winter, and were turned back, and lost their respective wars shortly thereafter. Thus Eddie Izzard's joke that "Hitler never played Risk as a kid".