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 (players spend much of their time forming and betraying alliances with other players and forming beneficial strategies) 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 designed to be played by seven players, but can be played with as few as two, each controlling the armed forces of a major European power (or, with fewer players, multiple powers). 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.
Diplomacy was the first commercially published game to be played by mail (PBM); only chess, which is in the public domain, saw significant postal play earlier. Diplomacy was also the first commercially published game to generate an active hobby scene with amateur fanzines; only science-fiction, fantasy and comics fandom saw fanzines earlier. Competitive face-to-face Diplomacy tournaments have been held since the 1970s. Play of Diplomacy by e-mail (PBEM) has been widespread since the late 1980s.
Diplomacy has been published in the United States by Games Research, Avalon Hill, and Hasbro; the name is currently a registered trademark of Hasbro's Avalon Hill division. Diplomacy has also been licensed to various companies for publication in other countries. Diplomacy is also played on the Internet, adjudicated by a computer or a human gamemaster.
The idea for Diplomacy arose from Allan B. Calhamer's study at Harvard of nineteenth-century European history under Sidney B. Fay and from his study of political geography. Calhamer also drew inspiration from the card game of Hearts, in which he observed that players were at an advantage when they teamed up against the leader, and from the game of chess, which inspired him to use a limited number of spaces and pieces.
The rough form of Diplomacy was created in 1954, and its details were developed through playtesting until the 1958 map and rules revisions. Calhamer paid for a 500-game print run of that version in 1959 after rejection by major companies. It has been published since then by Games Research (in 1961, then a 1971 edition with a revised rulebook), Avalon Hill (in 1976), by Hasbro's Avalon Hill division (in 1999), and now by Wizards of the Coast (in 2008) in the US, and licensed to other boardgame publishers for versions sold in other countries. Among these are Parker Brothers, Waddingtons Games, Gibsons Games, and Asmodée Editions.
The first copy of the first print run was sold by the Calhamer estate through auction in 2017.
The board is a map of 1901 Europe plus Turkey, Syria and North Africa. It is divided into fifty-six land regions and nineteen sea regions. Forty-two of the land regions are divided among the seven Great Powers of the game: Austria-Hungary, Great Britain, France, Germany, Italy, Russia, and Turkey. The remaining fourteen land regions are neutral at the start of the game.
Thirty-four of the land regions contain "supply centers", corresponding to major centers of government, industry or commerce (e.g., Vienna and Rome); twenty-two of these are located within the Great Powers and are referred to as "home" supply centers. The remaining twelve are located in the neutral provinces. The number of supply centers a player controls determines the total number of armies and fleets a player may have on the board, and as players gain and lose control of centers, they may build (raise) or must remove (disband) units correspondingly.
The land provinces within the Great Powers which contain supply centers are generally named after a major city in the province (e.g. London and Moscow) while the other land provinces within the Great Powers are generally named after a region (e.g. Bohemia and Apulia). Neutral land provinces are generally named after countries (e.g. Serbia and Belgium).
All players other than Britain and Russia begin the game with two armies and one fleet; Britain starts with two fleets and one army, and Russia starts with two armies and two fleets, making it the only player to start the game with more than three units. Only one unit at a time may occupy a given map region. Balancing units to supply center counts is done after each game-year, which involves two seasons of play: Spring and Fall.
At the beginning of the game, the twelve neutral supply centers are typically captured within the first few moves. Further acquisition of supply centers becomes a zero sum dynamic with any gains in a player's resources coming at the expense of a rival.
Although the game starts in 1901, the map generally reflects the political boundaries of Europe in 1914, just before the outbreak of the Great War. Bosnia is already annexed to the Austro-Hungarian Empire, and the Balkans reflect the results of the wars of 1912 and 1913 in the region.
On the other hand, Montenegro is shown as part of Austria-Hungary. Additionally, North Africa and Tunis start the game as neutral, despite these regions being part of the French colonial empire in 1914. Finland and Syria are both parts of Great Powers, as Finland was part of the Russian Empire, and Syria was part of the Ottoman Empire in 1914. Tunis is used rather than Tunisia on most boards. North Africa is a single province covering parts of Algeria and Morocco.
Comparison with other war games
Diplomacy differs from the majority of war games because:
Players do not take turns sequentially; instead all players secretly write down their moves after a negotiation period, then all moves are revealed and put into effect simultaneously.
Social interaction and interpersonal skills make up an essential part of the play.
The rules that simulate combat are strategic, abstract, and simple—not tactical, realistic, or complex—as this is a diplomatic simulation game, not a military one.