At bridge, artificial intelligence defeats eight world champions.

At the bridge, artificial intelligence has defeated eight world champions, a game where human dominance has resisted the march of the robots until now.

Because bridge players operate with imperfect knowledge and must react to the actions of numerous other players, the triumph marks a new milestone for AI because it is a scenario that is significantly more similar to human decision-making.

In chess and Go, on the other hand, where AIs have already defeated human champions, a player has only one opponent at a time, and both players have access to all information.

“What we’ve seen represents a fundamentally important advance in the state of artificial intelligence systems,” said Stephen Muggleton, a professor of machine learning at Imperial College London.

NukkAI, a French startup, claimed its AI’s triumph on Friday, at the conclusion of a two-day tournament in Paris.

The human champions had to play 800 consecutive deals divided into 80 sets of ten in the NukkAI challenge. It didn’t include the game’s initial bidding phase, in which players come to an agreement that they must later fulfill by playing their cards.

Each champion played their own and their “dummy” partner’s cards against a pair of opponents. These opponents were the best robot champions in the world to date – robots that have won many robot competitions but that are universally acknowledged to be nowhere near as good as expert human players.

The AI – called NooK – played the same role as the human champion, with the same cards and the same opponents. The score was the difference between those of the human and the AI, averaged over each set. NooK won 67, or 83%, of the 80 sets.

Jean-Baptiste Fantun, the co-founder of NukkAI, said he had been confident the machine – which the company has been developing for five years – would triumph in thousands of deals, but with only 800 it was touch-and-go.

Announcing the results, the mathematician Cédric Villani, winner of the Fields medal in 2010, called NukkAI “a superb French success story”.

AI researcher Véronique Ventos, NukkAI’s other co-founder, calls NooK a “new generation AI” because it explains its decisions as it goes along. “In bridge, you can’t play if you don’t explain,” she says.

The game relies on communication between partners.