Jeffrey Otterby, a middle school teacher in Illinois, is facing an epidemic of student distraction. When his seventh-graders are supposed to be learning social studies, they are glued to their school-issued Chromebooks. He has taken to standing in the back of the room to monitor their screens, where he can see the online game they’re all playing:

Chess.

“I guess I’m happier they are playing chess rather than some shoot-’em-up game. Actually, I love it,” said Otterby, a chess enthusiast. “I just need them to do it at a better time.”

Otterby’s crop of middle-schoolers in the St. Charles Community district are not alone. Across the country, students from second grade to senior year have stumbled across a new obsession, which is, in fact, a centuries-old game. Interviews with teachers and students in eight states paint a picture of captivated students squeezing games in wherever and whenever they can: at lunch, at recess and illicitly during lessons, a phenomenon that is at once bemusing, frustrating and delighting teachers.