In a shortened lineout, extra forwards must keep retiring to the 10m offside line for the backs, or until the lineout is over.
Once a player arrives at the line of touch he cannot legally leave the lineout before the ball is thrown.
The exception is if the throwing team line up less than seven players the opposing team are allowed to reduce their numbers accordingly.
There are specific places where throwers and receivers must stand.
The opponent of the thrower must stand 2m back and 2m in from the line of touch, while the receivers should stand no more than 2m back from their team in the lineout.
If another player steps out of the lineout then that player is considered to be a second receiver and would be penalised for offside play. Before the ball is thrown in, there must be a gap of 1m between the shoulders of opposing players in the lineout.
Also, before the throw in, players may not hold, push, charge or obstruct an opponent.
The lineout begins when the ball leaves the hands of the throwing player. It must be straight so that it alights in a channel anywhere between the inside shoulders of the players in the lineout.
If it is not thrown in straight the opposing team can have their own throw in or take a scrum 15m infield.
A lineout can end in one of six different ways - it just gets easier and easier, doesn't it?
1. When the ball is thrown, knocked or kicked from the lineout.
2. When the ball or a player carrying it moves into the area between the touchline and the 5m line.
3.When the ball is handed to a player who is "peeling off".
4.When the ball is thrown beyond the 15m line or when a player takes it beyond that line.
5.When a ruck or maul is formed and all the feet of the players in the lineout move beyond the line of touch.
6.When the ball becomes unplayable in the lineout.
Players in the lineout may not jump or be lifted before the ball is thrown in, otherwise a free kick is awarded.
Players also cannot hold, push, charge or obstruct an opponent, nor can they lever off an opponent while jumping for the ball.
Players may jump in an endeavour to catch or deflect the ball, using both hands or the inside arm - they are not permitted to use the outside arm only.
A player may "peel off" the line of touch to catch the ball as it is knocked or passed back by a teammate.
This move was introduced during the 1963-4 All Blacks tour of Britain by captain and hooker Wilson Whineray and was then known as a "Willie-away".
Nowadays, if the ball is not received by this player, he must keep moving up and down the lineout until it has ended - if he stops moving he is considered as a second receiver and penalised.
The offside line for lineout participants is the ball once it has been thrown in, with participants offside if they are in front of the ball, unless they have jumped for it and crossed the line of touch.
Retire immediately and there is no penalty, unless they are serial offenders, doing so deliberately to disrupt the opponents' ball.
Spare forwards and the backs, except the halfback, must remain 10m back from the line of touch until the lineout has ended, with the referee usually holding up his hand to stop them advancing too soon.