Kingmaking in Press Diplomacy.

Humans play games like Diplomacy for more reasons than just trying to win. For example, when they know they are losing, they may choose to aid an opponent rather than concede. This paper presents Lyre, an agent skilled at playing/communicating in Diplomacy and adept at working towards the benefit or harm of a given opponent - kingmaking. We parallel Lyre's kingmaking with real human Diplomacy games and analyze how Lyre can best play kingmaker. Results show statistically significant benefit in Lyre's boardplay, negotiation, and kingmaking.