With most information hidden, the game Stratego had stumped AI, until now

Stratego hides the identity of all 40 pieces from the opponent, creating over a decillion possible setups, which stumped earlier AI systems. Ataraxos pairs self-play training on 163 million games with a second neural network that estimates the opponent's hidden pieces so it can search ahead before each move; it beat the best human player 15 games to one, with four draws, using just 16 GPUs.

Summary written with AI by HowTechMoves, based on reporting by Ars Technica.