Diplomacy is a strategic board game classic developed by Allan B. Calhamer and originally released in 1959. It is a game about negotiations, alliances and promises you either live up to or break.

Seven players take the role of seven nations which are struggling for power in the Europe of the beginning 20th century:

• England
• France
• Germany
• Italy
• Russia
• Austria-Hungary
• Turkey

The goal of the game is to conquer and control the mayority of so called supply centers of which there are a total of 34 on the map. Whoever controls the most supply centers (also known as SC, or dots) at the end of the game wins it.

The game consists of phases of negotiation and phases of movement.

During the negotiation phases the players talk to each other privately or in small groups to forge plans, enter alliances, make promises or propose strategies. After the negotiations everyone writes down the orders for his units in secret.

During the movement phase all written orders of all players are then executed simultaneously. It now shows who kept his promises, who works with whom and who you can really trust.

If a player conquers new supply centers he can build new units, if he loses centers he needs to disband units.

The complete rules in PDF are available from Avalon Hill. There is also a Wikipedia article on Diplomacy available.