Page "Board game" Paragraph 49

Another important feature of a game is the importance of diplomacy, i. e. players making deals with each other.

A game of solitaire, for obvious reasons, has no player interaction.

Two player games usually do not involve diplomacy ( cooperative games being the exception ).

Thus, negotiation generally features only in games for three or more people.

An important facet of The Settlers of Catan, for example, is convincing people to trade with you rather than with other players.

In Risk, two or more players may team up against others.

Easy diplomacy involves convincing other players that someone else is winning and should therefore be teamed up against.

Advanced diplomacy ( e. g. in the aptly named game Diplomacy ) consists of making elaborate plans together, with the possibility of betrayal.