The Elo rating system is a method used to calculate the relative skill levels of players in two-player games, such as chess. Named after its creator, Arpad Elo, the system assigns a numerical rating to each player, which changes based on the outcome of matches. When a player wins, their rating increases, while the opponent's rating decreases. The system is designed to be self-correcting, meaning that a player's rating will adjust over time as they compete against different opponents. This allows for a more accurate representation of a player's skill level, making it useful in various competitive settings beyond chess, including video games and sports.