The Great War at Sea series hypothetical situation of possible naval action between US and Japan in the 1930s. Game is based on actual US navy plans. Players plot their task forces moves on the strategic map and when contact is made combat is fought on the tactical map. Also published in Separate Volume #11 of Command Magazine Japan. The early boxes included a separate 4 pages insert trying to link the operational and tactical levels of the game that was tittled "Great War at Sea System Advanced Tactical Rules". Avalanche Press in 2008 released a comb bound book called Great War at Sea: South China Sea which used the map from War Plan Orange.