Chess has an undeniable mystique. You've seen it in the movies: Xavier vs. Magneto; Holmes vs. Moriarty; Frank vs. HAL. No dice, no random deal of cards, just mortal enemies locked in a war of wits.

As computers get better at chess, their games look more human. Their moves seem more connected to known strategic plans, and when they aren’t, the logic can still often be discerned by experts. But ...