> The NukkAI challenge required the human champions to play 800 consecutive deals divided into 80 sets of 10. It did not involve the initial bidding component of the game during which players arrive at a contract that they must then meet 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.

Seems like two pretty hefty caveats. Why not pit their best AI against humans directly? And can someone with a better understanding of the game explain how important the initial bidding round is?