Up to 4 people can play, one controlling each German army group (North, Center, and South), and one playing Russia. Russia gets 5 factories to place in the cities of their choosing at the beginning of the game. Each produces a specific unit type (2 infantry, 1 armor, 1 fighter, 1 bomber). Germany can't see anything in Russian cities. Russia keeps its units and factories hidden from view on a city card. When Russian troops move out of cities, they are moved from the city card to the main board.Railroads connect many of the Russian cities, which they can use to non-combat troops from city to city hidden from German view. Germany may try to cut the rails to limit Russian movement. Germany may scout Russian cities with a bomber to try and find out what is there, however, you can't scout and attack on the same army group's turn. Therefore, one army group must scout, and the next in the turn sequence can attack.The German players must work closely together in this game. German troops may be transferred from one army group to another, and are then controlled by that new groups player. Because of the hidden units, it is a game of high tension on both sides. Most of the time Germany isn't really sure what Russia has in a city it is about to attack. And, most of the time, Russia has nowhere near enough troops to defend everything they need to defend. There is a lot of cat and mouse, educated guessing, and downright devious strategy ('Hum, he would expect me to do this, so I'll do that. But he might be counting on me taking the less obvious choice...'The goal is for Germany to take Moscow, but to do this, they almost always need to take out the Russian factories which are producing units closer to the front. To make matters worse, Russia can dismantle, and move each of their factories once to another city. So, just when you think you have it all figured out... We're usually nervous wrecks by the end of a game...and usually ready to start another one right away! - BoardGameGeek