HAMBURG, Germany— Max Deutsch went through a month of training before he traveled across the ocean, sat down in a regal hotel suite at the appointed hour and waited for the arrival of the world’s greatest chess player.

Max was not very good at chess himself. He’s a 24-year-old entrepreneur who lives in San Francisco and plays the sport occasionally to amuse himself. He was a prototypical amateur. Now he was preparing himself for a match against chess royalty. And he believed he could win.

The unlikely series of events that brought him to this stage began last year, when Max challenged himself to a series of monthly tasks that were ambitious bordering on absurd. He memorized the order of a shuffled deck of cards. He sketched an eerily accurate self-portrait. He solved a Rubik’s Cube in 17 seconds. He developed perfect musical pitch and landed a standing back-flip. He studied enough Hebrew to discuss the future of technology for a half-hour.