|Part of a series on|
A military exercise or war game is the employment of military resources in training for military operations, either exploring the effects of warfare or testing strategies without actual combat. This also serves the purpose of ensuring the combat readiness of garrisoned or deployable forces prior to deployment from a home base.
War games involving two or more countries allows for better coordination between militaries, observation of enemy's tactics, and is a visible show of strength for the participating countries.
Exercises in the 20th and 21st centuries have often been identified by a unique codename, such as Cobra Gold, in the same manner as military contingency operations and combat operations like Operation Phantom Fury.
The modern use of military exercises grew out of the military need to study warfare and to 'reenact' old battles for learning purposes. During the age of Kabinettskriege (Cabinet wars), Frederick the Great, King of Prussia from 1740 to 1786, "put together his armies as a well-oiled clockwork mechanism whose components were robot-like warriors. No individual initiative was allowed to Frederick's soldiers; their only role was to cooperate in the creation of walls of projectiles through synchronized firepower." 
This was in the pursuit of a more effective army, and such practices made it easier to look at war from a top-down perspective. Disciplined troops should respond predictably, allowing study to be confined to maneuvers and command.
The stunning Prussian victory over the Second French Empire in the Franco-Prussian War (1870–71) is sometimes partly credited to the training of Prussian officers with the game Kriegspiel, which was invented around 1811 and gained popularity with many officers in the Prussian army. These first wargames were played with dice which represented "friction", or the intrusion of less than ideal circumstances during a real war (including morale, meteorology, the fog of war, etc.).
21st century militaries still use wargames to simulate future wars and model their reaction. According to Manuel de Landa, after World War II the Command, Control and Communications (C3) was transferred from the military staff to the RAND Corporation, the first think tank.
Von Neumann was employed by the RAND Corporation, and his game theory was used in wargames to model nuclear dissuasion during the Cold War. Thus, the US nuclear strategy was defined using wargames, "SAM" representing the US and "IVAN" the Soviet Union.
Early game theory included only zero-sum games, which means that when one player won, the other automatically lost. The Prisoner's dilemma, which models the situation of two prisoners in which each one is given the choice to betray or not the other, gave three alternatives to the game:
This modelization gave the basis for the massive retaliation nuclear doctrine. The zero-sum fallacy and cooperative games would be theorized only later, while the evolution of nuclear technology and missiles made the massive retaliation nuclear strategy obsolete.