The main international tournaments organised by the ICC include the ICC World Test Championship, the World Cup and the T20 World Cup. The World Cup is held every four years; it involves all the Test-playing nations and a number of teams advancing from the immediately preceding ICC World Cup Qualifier. The T20 World Cup, which is generally held every two years and, as in the latest competition, involves the ten full ICC members and six associate members who qualified through a qualifier competition, the ICC World Twenty20 Qualifier. The ICC also used to organise the now defunct ICC Champions Trophy, previously known as the ICC Knockout Cup, a shorter tournament that was held every four years in between World Cups.