The allocation of teams for the second season was very similar to that of the first: 12 teams from the RFU Championship, the second tier of English rugby 3 Irish provinces represented by 'A' teams 3 top clubs from the Scottish Premiership, the second tier of Scottish rugby 6 top clubs from the Principality Premiership, the second tier of Welsh rugby. The format closely mirrored that of the first season, the only difference being the introduction of a quarter final stage The teams were divided into four pools of six, playing over five weekends during the Autumn International and Six Nations windows, with quarter-finals on 5 or 6 March, semi-finals on 23 April and the final on 7 May. Each team played each of the other five teams in its pool once (home or away), with the top two teams in each pool qualifying for the knock-out stages: 2011–12 Competition The allocation of teams for the third season was identical to that of the second season: 12 teams from the RFU Championship, the second tier of English rugby 3 Irish provinces represented by 'A' teams 3 top clubs from the Scottish Premiership, the second tier of Scottish rugby 6 top clubs from the Principality Premiership, the second tier of Welsh rugby. The pool stage saw a change in format and consisted of six pools of four teams playing cross-pool matches, giving each team two home and two away matches. Matches between English teams were played mid-week. Pool matches took place from 21 September to 18 December. The top team from each pool qualified for the quarter-finals, together with the two runners–up with the best records. 2012–13 Competition The competition was considerably revamped, with expansion from 24 to 32 teams playing each other home and away in the pool stages (previously, pool matches were played home or away). The allocation of teams for the fourth season was therefore: 12 teams from the RFU Championship, the second tier of English rugby 4 Irish provinces represented by 'A' teams 4 top clubs from the Scottish Premiership, the second tier of Scottish rugby 12 clubs from the Principality Premiership, the second tier of Welsh rugby. The pool stage saw a considerable change in format and consisted of eight pools of four teams, giving each team three home and three away matches. Pool matches took place on the same weekends as the Heineken and Amlin