11 Days War is a two-player wargame, covering the final Central Powers offensive on the East Front, February to May 1918 (Operation Faustschlag), to include both the initial 11 days of offensive operations against the Bolsheviks and the ensuing pursuit in the Ukraine. The game pits the Central Powers (Germany, Austria-Hungary, their allies) against the Bolsheviks (or Reds, plus their allies). Additionally, there are third power forces called Greens which may come under the control of either player. There are three scenarios, representing different starting situations. The game system models warfare in the chaotic situation of the Eastern Front during the opening of the Russian Civil War. Further, the movement rules model the situation of operating in later Winter and Spring thaw, where railroads were vital.
Each game turn represents one to ten days of operations. Each hexagon (hex) on the map represents 60 kilometers (40 miles). Each unit represents anything from a brigade up to corps. Strategic markers represent specialized forces, such as airpower, and agitprop (agitation and propaganda).