The X-League () is the top-level Gridiron football league in Japan. It was founded in 1971 as the Japan American Football League, and changed its name to the X League in 1997. There are four divisions (X1 Super, X1 Area, X2, and X3) among which there is promotion and relegation. Teams are split into different divisions or blocks, depending on the tier. There are two types of teams, one being a company team in which only employees of that particular sponsoring company may play, and the other being a club team for which anyone can try out. Game rules are based on those of the NCAA college division in the United States, with the exception of the length of quarters, which are 12 minutes instead of 15 during the first stage of the season. The Japanese national team, which has won the first and second editions of the American Football World Cup and was runner-up, finishing second to the American team, in the 2007 installment of the tournament, was made up almost entirely of players from this league. Americans are often recruited to play for X League teams, with a strict rule of four per team. No more than two foreign players per team are allowed on the field of play at a time. Season format The league is split into 4 tiers: X1 Super, X1 Area, X2 and X3. There are two spring tournaments as well which are used by teams to ready themselves and evaluate new players before the fall season. One is the larger Pearl Bowl which teams from eastern Japan compete in, and the other is the Green Bowl for teams in western Japan. Regular season The top tier, X1 Super, includes 12 teams split into 2 divisions of 6 teams who play a 5 game regular season. The second tier, X1 Area, contains 8 teams while X2 comprises 19 teams, and X3 with 16 teams. The teams in X1 Area is divided into three groups with each team playing six games, three inside the group and three outside. The top tier X1 Super has 2 divisions, A and B, made up of teams from all over Japan. The next league down, X1 Area, has just one division between all 8 teams. The next two leagues below, the X2 and X3, contain east, west, and central divisions. The east and central divisions comprise teams mostly in