Diplomacy is a strategic board game created by Allan B. Calhamer in 1954 and released commercially in the United States in 1959. Its main distinctions from most board wargames are its negotiation phases and the absence of dice and other game elements that produce random effects. Set in Europe in the years leading to the First World War, Diplomacy is played by two to seven players, each controlling the armed forces of a major European power. Each player aims to move their few starting units and defeat those of others to win possession of a majority of strategic cities and provinces marked as "supply centers" on the map; these supply centers allow players who control them to produce more units. Following each round of player negotiations, each player can issue attack and support orders, which are then executed during the movement phase. A player takes control of a province when the number of provinces that are given orders to support the attacking province exceeds the number of provinces given orders to support the defending province.

A strategy game or strategic game is a game in which the players' uncoerced, and often autonomous, decision-making skills have a high significance in determining the outcome. Almost all strategy games require internal decision tree-style thinking, and typically very high situational awareness.