A chess engine is a computer program designed to play chess at a high level. It analyzes positions on the chessboard and calculates the best possible moves using algorithms and evaluation functions. Chess engines can assess millions of positions per second, making them powerful tools for both players and analysts. Many chess engines, like Stockfish and AlphaZero, are used by players to improve their skills or analyze games. They can also compete against each other in tournaments, showcasing their advanced strategies and tactics. Chess engines have revolutionized the way the game is studied and played, providing insights that were previously unavailable.