22/07/2026
How Does a Computer Play Chess?
A Fascinating Journey into the World of Artificial Intelligence
"Dad... I lost again!" Raghav said disappointedly, staring at the computer screen.
His father smiled and sat beside him.
"What happened? Were you playing another game of chess against the computer?"
"Yes! I thought that after practicing every day, I would finally win today. But I played three games in a row, and the computer defeated me every single time."
His father smiled and replied, "Don't be discouraged. A computer has no hands, no eyes, and no human brain. Yet, behind it works such a powerful system that it can challenge even the world's greatest chess players."
Raghav's eyes lit up with curiosity.
"But Dad, how does a computer play chess so accurately?"
This is not just Raghav's question. Every chess student wonders about this at some point. Today, let's uncover the mystery.
The Beginning of Chess-Playing Machines
The history of computer chess did not begin with modern computers. Around 250 years ago, in 1770, a remarkable machine called the Mechanical Turk amazed the world. It appeared as a man wearing a turban, sitting at a chessboard and playing against human opponents. People believed that the machine could actually think and play chess on its own.
However, years later, the truth was revealed. Hidden inside the cabinet was a skilled chess player who secretly controlled every move using a system of levers. The Mechanical Turk was not a technological breakthrough—it was an ingenious illusion.
The First True Automatic Chess Machine
In 1912, Spanish engineer Leonardo Torres Quevedo created El Ajedrecista, the world's first genuine automatic chess-playing machine. Unlike the Mechanical Turk, there was no hidden player inside. The machine could detect the positions of the pieces, make its own decisions, and play a limited form of chess automatically.
This invention marked the beginning of computer chess.
In 1950, renowned mathematician Claude Shannon published a groundbreaking paper explaining how computers could play chess. Soon afterward, Alan Turing developed Turochamp, one of the first chess programs. Although computers of that era were far less powerful than today's smartphones, they laid the foundation for modern artificial intelligence.
What Is a Chess Engine?
Today, when you play chess on a computer or smartphone, you are usually playing against a chess engine.
A chess engine analyzes every position and selects the best possible move. It mainly consists of four important components:
1. Board Representation – The engine stores the complete position of every piece in its memory.
2. Move Generator – It generates every legal move available in the current position.
3. Evaluation Function – It evaluates the position to determine which side is better, whether the game is equal, or whether one player has a winning advantage.
4. Search Algorithm – This is the heart of the engine. It examines millions of possible moves within seconds, looks several moves ahead, and chooses the strongest continuation.
The Power of Databases
A chess engine does more than calculate moves—it also relies on enormous databases.
An Opening Book contains thousands of well-studied opening variations. This allows the engine to play strong opening moves instantly without recalculating everything from scratch.
An Endgame Tablebase stores every possible position with only a few pieces remaining on the board. It knows with perfect accuracy whether a position is a win, draw, or loss.
Humans vs. Computers
Many experts once believed that computers would take decades to defeat the World Chess Champion.
In 1957, researchers at Carnegie Mellon University predicted that computers would eventually become strong enough to challenge the world's best players.
Around the same period, Scottish International Master David Levy famously bet that no computer would defeat him in a chess match within the next ten years. He won the bet in 1978 by defeating the chess program Chess 4.7 by a score of 4.5–1.5 in a six-game match. However, Chess 4.7 also made history by defeating a master-level player in a blitz game.
Computer chess then advanced at an incredible pace.
The year 1997 became a historic milestone. Reigning World Champion Garry Kasparov faced IBM's supercomputer Deep Blue in a six-game match. Deep Blue won 3.5–2.5, becoming the first computer to defeat a reigning World Chess Champion under standard tournament conditions.
This victory marked not just a chess achievement but a major breakthrough in artificial intelligence and computer science.
Today, engines such as Stockfish, Leela Chess Zero, and other modern programs analyze millions—or even billions—of positions every second. Defeating these engines has become nearly impossible, even for the world's strongest grandmasters.
At the same time, these engines have become invaluable learning tools, helping players analyze games, discover mistakes, and improve their understanding of chess.
What Can We Learn from Computers?
Today, a computer is not merely an opponent—it is one of the best chess coaches available.
After every game, it identifies mistakes, recommends stronger moves, and explains where improvements can be made.
Therefore, losing to a computer should never be discouraging. Every defeat becomes an opportunity to learn something new.
Conclusion
A computer plays chess not because it possesses human emotions or intuition, but because it combines extraordinary calculation speed, powerful search algorithms, accurate evaluation methods, and vast databases of chess knowledge.
Every chess student should remember that the real goal is not to defeat the computer, but to learn from it. With every game we analyze, we become a stronger player than we were yesterday.
Written by
Laxman Machhindra Pawar
Mobile: +91 84212 14874
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