Operation Barbarossa - covering the initial onslaught of June through December 1941. The German invasion of Russia in World War II, portrayed with army and corps scale units, at 65 km per hex. Each game turn is one month. One of GDW's Series 120 games, a line of introductory wargames spanning various historical eras. The games in the series had 120 counters and were supposed to be playable in 120 minutes or less, hence the name.