The Rugby Football League has revealed full details of the new structure for the 2015 Super League and Championship.
Clubs will play 23 games in two divisions of 12 and then be split into three pools of eight.
The top Super Eights group will then play seven further games, with the top four at that stage progressing to contest places in the Grand Final.
Four further top-flight clubs for the following season will come from the middle qualifiers pool.
While the top three will automatically enter the Super League, the teams in fourth and fifth will play a one-off game for the 12th place.
The final group of eight, the Championship Shield, will also feature a top-four play-off, with the bottom two clubs in that group dropping into a third tier renamed as League One.
That division grows to 14 clubs, with the bottom five in the current Championship second tier joining the existing nine teams, while Coventry Bears come in to replace the club that wins promotion this term.
Those clubs will also compete for the League One Cup, with the 2014 National Conference League Grand Final winners and the RFL Conference Challenge Cup winners also entered.
At present 14 clubs play in the Super League, although both Bradford Bulls and London Broncos have already been relegated, reducing it to 12 teams for next season.
|Changes in brief|
|Super League's top eight will split after 23 games (including Magic Weekend) into a seven-game group and the top four will contest the play-offs in a semi-final format.|
|The middle tier of eight qualifiers - comprising the bottom four from Super League and top four from the Championship - will play seven games - the top three and 4th v 5th play-off winners go up.|
|League One - formerly Championship One - will grow to 14 teams, with Coventry Bears entering the competition from 2015 and the end of the 2014 season bottom five in the Championship dropping down.|
|Bonus points, currently used in the bottom two divisions, will be considered for use in Super League between now and the start of the season.|
|Top eight SL clubs go into the Challenge Cup sixth round, bottom four SL clubs into the fifth, Championship clubs in round four, League One clubs in round three.|
"The changes will ensure that every minute of every match in every competition matters and are being implemented following the most comprehensive consultation process in the sport's history," RFL chief executive Nigel Wood said.
"The return of promotion and relegation in a format that is financially sustainable for all clubs should ensure fans are entertained from February to October, with an exciting season punctuated by a series of world-class events commencing with the World Club Challenge and finishing at Old Trafford with the Super League Grand Final."
Meanwhile, in the Challenge Cup, Super League's top eight clubs will join the competition at the last 16 stage from next season.
Additional changes to the Challenge Cup also include the entry of the bottom four Super League clubs at the fifth-round stage, with Championship clubs in at round four and League One teams at round three.
Super League's salary cap has not changed, although the Championship cap has increased to £1m and will be reviewed on an ongoing basis.
Magic Weekend will continue for the 12 top-flight outfits, although there has been no confirmed venue, while the Championship will have a similar Summer Bash event to take place in Blackpool.