You don’t need a license to call yourself a “chess detective,” as Kenneth Regan is often described. But over-the-board cred helps. Regan began playing chess with his father at five years old and beat him after six months. At 13, he became the youngest person to achieve the title of “master” since Bobby Fischer. Regan later dropped off the grandmaster track, preferring to study math. (He still achieved the title of “international master.”) He racked up degrees at Princeton, Oxford, and Cornell, then took a job teaching at Buffalo and dedicated himself to untangling abstruse theoretical questions—particularly the famous problem known as “P vs. NP,” which is tangentially related to whether or not it’s possible to “solve” chess. His focus shifted in 2006, when the Russian champion Vladimir Kramnik visited the bathroom numerous times during a game, fueling suspicions of cheating—a scandal known as “toiletgate." Regan said he felt “called” to weigh in online. He determined that Kramnik’s moves, while similar to those of a chess engine, were not statistically significant enough to justify the accusations. Regan soon began building the software that would become his calling card. When Regan debuted his anti-cheating program in 2011, he faced “widespread skepticism,” he says; at the time, the International Chess Federation “tended to minimize cheating.” But with the rise of online chess and the proliferation of engines, cracking down on cheating—much like anti-doping measures in other sports—became a matter of the game’s survival. Now, Regan’s anti-cheating work may be his legacy. Read more at the link in our bio. Photograph by Sinna Nasseri (@strange.victory) for TIME