War Games

Screen shot of war game

War games refer to two activities, one professional, the other a hobbyist pursuit.

Military simulations. The Prussian Army first began training its officers using a war game (German: Kriegspiel) as early as 1811. The notion caught on with other armed forces, including the Japanese, who extensively wargamed proposed operations, such as the Centrifugal Offensive (including the Pearl Harbor strike) and the Midway operation. Such war games were deadly serious, and the more sober designation military simulations became the preferred term after wargaming as a hobby became popular in the postwar era. Military simulations of the Pacific War era were typically conducted with boards, markers, and dice, according to a set of rules, with the two opposing sides in separate rooms with umpires giving only that information on what the other team was doing that they could have been aware of through their own side's intelligence.

Such military simulations could be effective at getting military leaders to think about possible outcomes and hazards of an operation. Their ability to predict likely outcomes was more problematic, requiring that the rules be tuned to reflect actual experience. This could be done for past engagements but required a dangerous level of extrapolation to future conflicts with new tactics and technology. Japanese wargaming of the Centrifugal Offensive actually overestimated the likely casualties, but the war games conducted prior to the Midway operation correctly predicted that there was potential for a devastating American ambush. This disquieting result was simply ignored.

Wargaming was also subject to "mirror imaging", in which wargamers tended to project their own capabilities onto the enemy. Since every navy assumed the best of its own capabilities and doctrine, projecting those capabilities and doctrine on the enemy was simply being conservative. American wargamers assumed that the Yamatos were similar to the Iowas, that the Japanese could not have oxygen-powered torpedoes when both the British and Americans had failed to make them work, and that Japanese ships had similar resistance to damage as American ships. In fact, the Yamatos and Iowas were quite dissimilar, the Japanese had deployed the oxygen-powered Long Lance torpedo, and Japanese ships were generally less resistant to damage and had inferior damage control compared with American ships.

Wargaming was adopted by the U.S. Naval War College just prior to the First World War and championed postwar by Admiral William S. Sims. American military simulations performed at the Army and Naval War Colleges traditionally denoted American forces as Blue, with other colors used to designate other powers. For example, England was Red, Germany was Black, and Japan was Orange. These designations were adopted for contingency plans in the event of war, so that Plan Orange was the contingency plan for a war with Japan, while Rainbow was a set of contingency plans for war with various combinations of allies and enemies. The Navy War College published extensive Maneuver Rules and Combat Effects Tables which, by 1941, amounted to several hundred pages. The rules were strictly followed, with umpires intervening only to rule on situations overlooked by the rules. Logistics were an important part of the maneuver rules and all ranks were encouraged to critique the results. Simplified rules were used for fleet exercises, and the results were taken very seriously; admirals were known to be passed over for promotion if they blundered in fleet exercises.

In Japanese war games, the umpire had much greater latitude to overrule the formal rules than in American war games. The war games also had a tendency to brush aside logistical constraints, sometimes simply assuming that fleet at sea would somehow be refueled. The war games were often highly political, one of their purposes being to build consensus by acquainting officers with operational plans and drawing out any opposition to the plans. This was particularly evident during the war games staged by Yamamoto to explore plans for the Pearl Harbor operation.

By the end of the war, the Allies had developed operational research, of which military simulation was an important component, into a sophisticated mathematical science. For example, the ASWORG (Antisubmarine Warfare Operational Research Group) was organized by the U.S. Navy in March 1942, and it and its British counterparts greatly improved Allied antisubmarine tactics.

Wargaming as a hobby. Warfare has always fascinated even when it has also appalled. Wargaming as a hobby became popular during the 1970s and 1980s, when the medium was almost always boards and cardboard counters, with outcomes usually determined by dice rolls. The advent of home computers transformed hobby wargaming into a largely computer-based activity.

This Encyclopedia was originally inspired by the authors' interest in wargaming and much of the information in it has been organized with hobby wargame designers as a target audience.

Wargaming resources available at this site

Orders of battle:




    Chinese Communist




    New Zealand

    United States



Prange (1982)

Roscoe (1953) (accessed 2010-5-3)

Venzon (2003)

Zimm (2011)

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