K League 1 is the top professional football league in South Korea, established in 1983. It features 12 teams that compete annually for the championship title. The league operates on a system of promotion and relegation with K League 2, the second tier of South Korean football. Matches are typically held from February to December, with each team playing 33 games in a round-robin format. The league is known for its passionate fan base and has produced many talented players who have gone on to represent South Korea in international competitions.