DeepMind AI uses deception to beat human players in war game Stratego

An AI can defeat expert human players in the board game Stratego, which has more possible game scenarios than chess, Go or poker. The AI developed by the UK-based company DeepMind became one of the top-ranked online players of the Napoleonic-themed board game Stratego by learning to bluff with weaker pieces and sacrifice important pieces for the sake of victory. "To us the most surprising behaviour was [the AI's] ability to sacrifice valuable pieces to gain information about the opponent's set-up and strategy," says Julien Perolat at DeepMind. The game of Stratego involves two players trying to capture the opponent's flag hidden among an array of 40 game pieces. Most pieces consist of soldiers numbered from one to 10, with the higher-ranked soldiers defeating lower-ranked soldiers during encounters on the board. But players cannot see the identities of opponent game pieces unless two pieces from opposing armies encounter one another – unlike games such as chess or Go where both players can see everything.