Chess Engine

A chess engine is a program that analyzes positions and can calculates the strongest possible moves. It is the brain behind every analysis board, every evaluation bar on a live broadcast, and every piece of opening preparation at the professional level. The top chess engines today play at estimated ratings above 3500 — roughly 600 points stronger than any human, including the reigning World Champion.

If you have ever clicked “analyze” after a game, you have used a chess engine. The number hovering around +0.3 or -1.5 on your screen is the engine’s opinion, measured in pawns, of who holds the advantage. Most players interact with a chess game engine through a graphical interface, but the engine itself has no board, no pieces, no graphics — just raw calculation.

What is a Chess Engine?

A chess engine analyzes the starting position, searches all of the possible continuations, and delivers what is the best move. Stockfish evaluates up to ten million positions per second on standard hardware. Neural network engines like Leela Chess Zero evaluate far fewer positions but with deeper positional understanding — each evaluation is “smarter,” compensating for the lower volume.

Every serious player uses engines for preparation. Titled players check opening novelties, verify tactical ideas, and analyze their opponents’ games before tournaments. Commentators run them during live broadcasts. Coaches use them to identify mistakes in students’ play. Whether you are reviewing a classical Grandmaster game or checking a bullet chess blunder, the engine is the silent partner every chess player now relies on.

Best Chess Engines in the World

Chess engines compete in championships to find the best performing engines, events like TCEC (Top Chess Engine Championship) and Chess.com Computer Chess Championship. Here are the engines that define the current era.

Stockfish

Stockfish is the strongest chess engine available to the public, and has been for years. It originated in 2008 as a fork of an open-source engine called Glaurung, created by Norwegian programmer Tord Romstad. Italian developer Marco Costalba renamed it Stockfish — because it was “produced in Norway and cooked in Italy.” Since 2020, Stockfish has integrated NNUE (Efficiently Updatable Neural Networks), combining traditional search with neural network evaluation. It dominates every major engine competition and powers the analysis tools on Lichess and Chess.com. The online chess engine you are most likely using right now? Probably Stockfish.

Leela Chess Zero (Lc0)

Leela Chess Zero is an open-source engine inspired by Google DeepMind’s AlphaZero. Started January 2018 by Gary Linscott, Leela taught it’s self chess through self play and just starting with the rules of the game. Volunteers worldwide contributed computing power to train its neural networks. Leela reached the Grandmaster level by late 2018, and has been a close rival od Stockfish since. The style is notably different: more positional, more willing to sacrifice for long-term advantage, and capable moving to mimic a human like feel.

AlphaZero

AlphaZero is the engine that changed everything. Developed by Google DeepMind and revealed in December 2017, it taught itself chess from scratch in four hours of self-play — then demolished Stockfish 28–0 with 72 draws. DeepMind’s Demis Hassabis called its style “alien”: bold sacrifices, long-term positional squeezes, and moves that broke every convention. AlphaZero was never released to the public, but its influence is everywhere — every top chess engine now uses neural network technology it popularized.

Komodo Dragon

Komodo was built by programmer Don Dailey and Grandmaster Larry Kaufman starting in 2010. It earned a reputation for exceptional positional evaluation — when other engines could not find a plan, Komodo could create something from nothing. After Dailey’s passing in 2013, Mark Lefler continued development. In 2020, the team released Dragon, incorporating NNUE technology. Now owned by Chess.com, Komodo Dragon remains among the top three engines worldwide.

Rybka

Rybka or “little fish” in Czech, From 2005 - 2010 dominated computer chess under creator Vasik Rajlich. The engine won four World Computer Chess Championships before being stripped of those titles from plagiarism accusations. Despite the controversy, Rybka’s considerable influence on the engine development remains a significant chapter in the history of the game.

The Origins of Chess Engine Term

The concept of a machine playing chess is older than computers. 1770, Wolfgang von Kempelen, a Hungarian inventor, unveiled “The Mechanical Turk” , a mannequin in a cabinet that appeared to play chess autonomously. It beat Napoleon and Benjamin Franklin. However the invention was a fraud, hidden inside was a human master, operating the pieces.

It wasn't until 1912 when the first genuine chess-playing machine was created, when Spanish engineer Leonardo Torres y Quevedo created El Ajedrecista, a device that could win a king-and-rook endgame. In 1950s modern computer chess began when Alan Turing wrote the first chess-playing algorithm and IBM engineer Alex Bernstein built the first fully automated program — one that took eight minutes per move.

The word “engine” entered chess vocabulary in 1986, when a company called Sys-10 marketed their hardware under the brand name “Chess Engine.” As software separated from graphical interfaces through protocols like WinBoard and later the Universal Chess Interface, the term stuck: an “engine” became the calculating core behind the board you see on screen. World Champion Garry Kasparov was defeated by IBM’s Deep Blue in 1997, the reign of human supremacy over chess had ended.

Final Thoughts on Chess Engines

Chess engines have changed how the game is played forever, how it is studied, and watched. No top player prepares without one. No serious broadcast runs without an evaluation bar. The game has not been diminished by them — if anything, they have deepened the understanding, revealing layers of complexity that humans couldn't discover . Whether you are using an online chess engine to analyze your last game or following a TCEC superfinal with Stockfish and Leela, these programs are now inseparable from chess.