For a while in the mid-2000s, a refrigerator-sized box in Abu Dhabi was considered the greatest chess player in the world. Its name was Hydra, and it was a small super-computer—a cabinet full of industrial-grade processors and specially designed chips, strung together with fiber-optic cables and jacked into the internet.

At a time when chess was still the main gladiatorial arena for competition between humans and AI, Hydra and its exploits were briefly the stuff of legend. The New Yorker published a contemplative 5,000-word feature about its emergent creativity; WIRED declared Hydra “fearsome”; and chess publications covered its victories with the violence of wrestling commentary. Hydra, they wrote, was a “monster machine” that “slowly strangled” human grand masters.

True to form as a monster, Hydra was also isolated and strange. Other advanced chess engines at the time—Hydra’s rivals—ran on ordinary PCs and were available for anyone to download. But the full power of Hydra’s 32-processor cluster could be used by only one person at a time. And by the summer of 2005, even the members of Hydra’s development team were struggling to get a turn with thei