Liga 1 is the top professional football league in Peru, established in 1912. It features 18 teams competing annually for the championship title. The league operates on a system of promotion and relegation with the second tier, Liga 2. The season typically runs from February to December, with teams playing each other in a round-robin format. The top teams qualify for international competitions, such as the Copa Libertadores and Copa Sudamericana. Alianza Lima, Universitario, and Sporting Cristal are among the most successful clubs in the league's history.