Many of the most popular tabletop board games are designed for big groups—that’s what game nights are about, after all. But coordinating the schedules of a bunch of adults can be a puzzle more intimidating than the Saturday New York Times Crossword, so it’s nice to have options for a quiet night in with a partner, roommate, or friend.Two-player games have come a long way since checkers, backgammon, and Battleship, and today the best of them are just as complex and enthralling as any group game.We talked with experts, spent more than 30 hours researching, and played 47 different games to find the one-on-one games that most people will enjoy.