How Chess Computers Work – A Deep Dive

Chess computers have revolutionized the world of chess, making the game accessible, instructive, and challenging for players of all skill levels.

In this exploration, we will dive into the fascinating world of chess computers, unraveling how chess computers work, the technology behind them, their historical significance, and how they’ve transformed the way we play chess today.

A Historical Overview

The history of chess computers can be traced back to the mid-18th century, but the true breakthrough occurred in the mid-20th century. In 1950, British mathematician Alan Turing developed the first computer program explicitly designed to play chess.

However, it wasn’t until 1956 that the world saw the first electronic chess computer, the IBM 701, designed by Alex Bernstein. The machine could evaluate approximately 3,000 positions per second, marking the beginning of a new era in chess.

Algorithms and Evaluation

Chess computers operate through a combination of algorithms, databases, and extensive evaluation of chess positions. Here’s how it all comes together:

  • Opening Databases: Chess computers often use vast opening databases, which contain thousands of well-studied opening moves and their subsequent variations. These databases guide the computer’s early moves, ensuring a strong opening phase. Of the three phases in a chess game, the opening is known to be especially governed by theory and remembering variations, and this lends itself to the use of a computer.
  • Position Evaluation: At the core of a chess computer’s functioning is its ability to evaluate positions. This evaluation involves analyzing the board, assigning values to pieces and squares, and calculating the overall “score” for a position. A positive score indicates an advantage for White, while a negative score suggests an advantage for Black. This is the evaluation bar you see when you analyze your online game.
  • Minimax Algorithm: Chess computers utilize the minimax algorithm to explore potential moves and their consequences. This algorithm evaluates each move by minimizing the opponent’s best response and maximizing the computer’s potential advantage. It’s a mathematical problem, but as an engineer, I can tell you that it’s an extremely complex one.
  • Alpha-Beta Pruning: To save time and computational resources, chess computers employ the alpha-beta pruning technique. This method narrows down the search by ignoring branches that are unlikely to lead to a favorable outcome.
  • Endgame Tablebases: In the endgame, chess computers utilize endgame tablebases, which are pre-computed databases of all possible endgame positions. In an endgame, there are only a few pieces left on the board, which allows these tablebases to provide perfect play.

The Revolution Leader

Deep Blue, developed by IBM, is a legendary chess engine that made history in the world of chess. In 1997, it famously defeated the reigning world chess champion, Garry Kasparov, in a historic match.

Deep Blue’s success was a testament to the rapid advancements in computer chess and its ability to calculate millions of positions per second. This landmark victory marked a pivotal moment in the evolution of chess computers, demonstrating their immense potential to challenge and even surpass human grandmasters.

The Modern Chess Computer

Modern chess computers consist of chess engines: software programs that implement the algorithms and evaluation techniques described earlier. These engines work along with graphical interfaces that provide users with a user-friendly platform for playing, analyzing, and learning chess.

Famous chess engines like Stockfish, AlphaZero, and Leela are widely used by players and chess enthusiasts worldwide.

Chess engines have become invaluable tools for players of all levels. They can offer game analysis, suggest improvements, and provide valuable insights into positions. Additionally, they enable players to compete against computer opponents of various skill levels, from novice to grandmaster level, making them versatile training partners.

Impact on the Game

The advent of chess computers has had a profound impact on the game and its players:

Accessibility: Chess computers have made the game accessible to a global audience. With the ability to play online against computer opponents or other players, anyone with an internet connection can engage in a game of chess.

Learning and Improvement: Chess computers are excellent tools for learning and improvement. They provide immediate feedback and analysis, helping players identify and rectify their mistakes.

Training and Preparation: Chess professionals use computers extensively for training and preparation. They analyze opponents’ games, explore opening variations, and test different strategies with the assistance of chess engines.

Entertainment: Chess computers offer a source of entertainment, with various software and online platforms providing engaging features, such as interactive tutorials, puzzles, and historical game databases.

Historical Matches: Chess computers have made history by competing against and defeating world-class human players. These matches, like the iconic Kasparov vs. Deep Blue encounter, have captivated audiences and showcased the power of technology.


Chess computers have become integral to the world of chess. They are not just opponents but also invaluable partners for learning, training, and enjoyment.

The technology behind these machines, driven by sophisticated algorithms and vast databases, continues to evolve, making chess accessible and engaging for enthusiasts of all levels.

Whether you’re a grandmaster honing your skills or a beginner taking your first steps in the game, chess computers are there to support, challenge, and inspire.

If you have any questions or insights you’d like to share about chess computers or any other topic, please leave me a comment below. I’d love to have chat with you.

2 thoughts on “How Chess Computers Work – A Deep Dive”

  1. Thank you for this article Yusuf.

    I have often had phases of paying chess online. I play for a couple of weeks and then get bored because I’m not actually that good. I am usually able to play for quite a long time without losing pieces, but I never seem to be able to develop my pieces in order to progress towards winning a game.

    Obviously, your article looks at the machinations of chess computers. Would you be able to recommend a good chess app/site that I could use in order to learn and develop my own game?

    Thanks in advance,


    • Thank you very much for your comment, Simon.

      No need to look far! I recommend you take a look at my guide for beginners, I’m sure you’ll find it helpful.

      I have also written an article explaining chess tactics for beginners, as well as many articles under the “Beginner’s Guide” category that you can see in the header menu on the top.

      Feel free to ask any questions that come to mind, I’ll be more than happy to help.


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