The Czech First League, known as the Fortuna liga for sponsorship reasons, is a Czech professional league for football clubs. At the top of the Czech football league system, it is the country's primary football competition. In 2020–21 the league is contested by 18 clubs, operating a system of promotion and relegation with the Czech National Football League, the teams playing 34 games each. Seasons typically run from August to May, most games are played on Saturdays and Sundays with few games played on Fridays. All Fortuna liga clubs qualify for the Czech Cup.