Oakland, Calif.

After a recent Golden State Warriors game, Klay Thompson opened the Chess with Friends app on his phone. He wanted to show a match he was playing against teammate Andre Iguodala to someone he’d never met waiting for him outside the locker room. Thompson thought Magnus Carlsen might be able to offer some assistance.

Magnus Carlsen is the best chess player in the world, according to the official rankings of the sport’s governing body. Klay Thompson introduced himself to Carlsen as the best chess player on the Warriors, according to the official rankings of Klay Thompson.

“Based on loose facts,” he said, “but whatever.”

Thompson plays chess as often as he plays basketball: almost every day. “It’s a great game,” he said. He owns multiple chess boards at home. He carries a magnetic chess set on road trips. And he juggles several chess games on his phone, which is a problem for Thompson: He’s not good at chess on his phone.