An extension kit called the "First World War Module" was produced in the 1970s, containing rules and counters (mostly headquarter units with divisions being kept track of as abstract points), and instructions on how to amend the "War in Europe" maps (not included in the module) to simulate the First World War. Players are required to keep track of combat losses, which affect a country's morale and industrial ability, both of which will eventually, when a critical point is reached, reduce a nation's ability to withstand combat without retreating. This game has been out of print for many years and is now a rare collectors' item.