Chess Terms
Deep Blue (Chess Computer)

Deep Blue (Chess Computer)

Humans were the strongest chess entities on the planet for centuries. Even in the 1980s, it seemed laughable that a computer could ever defeat the strongest human players. Then in 1997, it happened—a computer defeated the world champion. Which computer, you ask? Deep Blue.

Let's learn more about this computer that changed history. Here is what you need to know about Deep Blue:


What Is Deep Blue?

Deep Blue was a chess computer developed by IBM. It is famous for defeating the chess world champion, GM Garry Kasparov, in their 1997 match. Deep Blue's victory was viewed as a symbolic testament to the rise of artificial intelligence—a victory for machine versus man.

The Deep Blue project (initially called ChipTest) was created by Feng-hsiung Hsu in 1985. In 1989 Hsu and other colleagues joined the IBM team to fully develop Deep Blue. An early version of Deep Blue played a match against GM Joel Benjamin, who joined the Deep Blue team as a GM consultant afterward.

By the time of the 1997 match, Deep Blue's alpha-beta search algorithm (the same type of search that is still used by many conventional computer engines today) along with its custom hardware allowed it to consider up to 200 million positions per second. Deep Blue was dismantled after the 1997 victory, with one of its two racks being displayed at the National Museum of American History and the other at the Computer History Museum.

Deep Blue
One of the Deep Blue racks on display at the Computer History Museum. Photo: James, CC.

Deep Blue Accomplishments

Deep Blue played two matches against Kasparov in the 1990s. In the 1996 match, Deep Blue lost 2-4 but still accomplished something that no chess computer had done before: it defeated the human world champion in a game—an unprecedented accomplishment. Kasparov is still widely viewed as the greatest player of all time.

Deep Blue Kasparov
Garry Kasparov. Photo: Owen Williams/Kasparov Agency, CC.

Many improvements were made to Deep Blue in between the 1996 and 1997 matches. When they met in the 1997 rematch, Deep Blue defeated Kasparov 3.5-2.5 in standard time controls and in a tournament setting. This incredible victory was groundbreaking and marked an achievement for the world of artificial intelligence.

Deep Blue Games

In the first game of the 1996 match, Deep Blue shocked the world by defeating Kasparov. It played the Alapin variation of the Sicilian and was able to force multiple structural weaknesses in Kasparov's position. After 24...exd5, all of Kasparov's pawns are either isolated, doubled, or both:

Deep Blue
Kasparov's pawn structure is in shambles.

Kasparov fought his way back to a balanced position but erred with 27...d4, and Deep Blue won the game convincingly. Here is the full game:

This second game example is the final game of the 1997 match. With the match score tied at 2.5-2.5, Kasparov played a solid line of the Caro-Kann Defense and purposefully played 7...h6, which invited an early piece sacrifice. Kasparov believed that Deep Blue would not sacrifice the piece, but it shockingly played 8.Nxe6!:

Deep Blue
Deep Blue played the early piece sacrifice with 8.Nxe6.

According to multiple sources, the Deep Blue team added this sacrificial line to Deep Blue's opening book on the same day of this game. After the sacrifice, Kasparov was blown off the board—he resigned on move 19 and lost the match.

Conclusion

You now know what Deep Blue is, what it accomplished, and more. Head over to Chess.com/CCC to watch chess computers play at any time on any day!