The Hacker Who Taught Computers to Play Chess: A Birthday Tribute to Ken Thompson
Happy Birthday to Ken Thompson! While most tech geeks know him for creating Unix (the “DNA” of your smartphone) or the Go language at Google, there’s a much cooler story to tell.
Ken is the reason computers are now unbeatable at chess. Here is how he did it.
Part 1: Building the “Illegal” Chess Machine
Back in the 1970s, computers were actually quite bad at chess. They were just too slow to think ahead. Ken Thompson and his friend Joe Condon decided that if standard software wasn’t fast enough, they would build their own “brain” from scratch.
They built a machine called Belle. It wasn’t a normal computer; it was a stack of custom-made circuit boards designed to do only one thing: calculate chess moves.
Belle was a beast. While other computers were checking 300 possibilities a second, Belle was scanning 160,000. It became the first computer to play at a “Master” level, proving that raw speed could beat human intuition.
The funny part? The U.S. government was actually scared of it! In 1982, they seized Belle at the airport, calling it a “high-tech weapon” because it was so much faster than anything else at the time. Ken actually had to pay a fine to get his chess set back from the government.
Part 2: Solving the Game from the Finish Line
Ken didn’t just want to win; he wanted the “ultimate truth.” He moved his focus to the end of the game, when only a few pieces are left on the board.
He created something called Endgame Tablebases. Instead of trying to guess the best move, Ken used math to work backward from the very last move (checkmate) all the way to the beginning of the endgame.
He essentially “solved” chess. His database didn’t have to “think”—it just looked up the answer. It knew with 100% certainty if a game was a win or a loss. He famously called this “Playing Chess with God” because the computer was literally perfect. It even proved that some famous human grandmasters had been wrong about certain moves for centuries!
The Legacy
Ken’s “brute force” approach changed everything. His work on Belle led directly to Deep Blue, the famous supercomputer that finally beat the world champion, Garry Kasparov, in 1997.
Today, if you play chess on your phone, you are playing against a “descendant” of Ken Thompson’s ideas. So, happy birthday to the man who showed us that with enough speed and a bit of “perfect math,” you can conquer almost any challenge.
