The Football League introduced the play-off system in 1986/87 season. The four teams who finish outside the automatic promotion places (usually those placed third to sixth) play-off over two-legged semi-finals and a final to decide who will play in the higher division the following season. Originally the play-offs involved one team from the higher division (who finished just above the automatic relegation places, e.g. Chelsea in 1988) and three teams from the lower division. Prior to 1990 the play-off finals were played over two legs and the finalists home grounds before changing to a single match at Wembley Stadium. Between 2001 and 2006 the play-off finals were hosted by the Millennium Stadium in Cardiff as Wembley was being re-built. The Championship Play-Off final (previously the Second Division Play-Off final until 1992 and the First Division Play-Off final from 1993-2004) is regarded as the richest single match in world football, promotion to the Premier League being value