During a game of rugby there are a number of lineouts caused by the ball being put into touch by either team.
Lineouts are an important and potentially potent set piece, but there is a lot of detail referees should be aware of, as well as players and if they are to fully exploit this potential.
The ball is in touch, or touch-in-goal, when the ball or carrier contacts the touchline, touch-in-goal line or anything beyond.
It is also in touch when a player already on the line or anything beyond, catches or holds the ball.
The opponents who last played the ball before it went into touch usually get to throw the ball into the lineout.
So, there is usually no drama if the ball carrier goes into touch, or the ball is unintentionally knocked, passed or thrown out, or the ball hits a player and goes into touch.
There have been a couple of changes to who throws the ball into a lineout this year.
If a player standing in touch (including on the touchline) picks up the ball, which is still in the field-of-play, then that player is deemed to have taken the ball out, regardless of whether the ball was moving or not.
Another change this year is when a knock-on occurs and the ball goes directly into touch, the opposing team has the option of taking the lineout or choosing a scrum at the place, but not less than 5m from touch.
As in the past, a player who is in touch or touch-in-goal may kick or knock the ball which has not reached the touch line back infield and play continues.
A player who is in the field-of-play can now jump up and return the ball to the field-of-play after it has crossed the plane of touch but before it or that player lands out of bounds.
The plane of touch is the vertical space rising immediately above the touch line or touch-in-goal line – essentially a vertical line above the touch lines.
Likewise, if a player carrying the ball crosses the touch line he may pass or throw the ball back into the field-of-play before he actually lands on the ground in touch.
These last two scenarios are changes to past law and are designed to give the game more continuity and make it "easier for players, coaches, officials and fans to understand".
The spectator I had an argument with about one of these scenarios last week was obviously unaware of the changes – I hope he reads this column so he can apologise gracefully next time we meet, but I doubt either will happen.
Apart from a conventional lineout, players can take a quick throw-in, but they do need to comply with four provisions.
First, the throw must be taken between the mark where the lineout would have been formed, and the thrower's own goal line.
The player throwing in must have both feet outside the field-of-play.
If either of these are not complied with, the quick throw is deemed to have been taken incorrectly and the lineout would take place where the quick throw was attempted.
Also, the ball must reach the 5m line before it touches the ground or a player, otherwise a free kick is awarded to the opposition on the 15m line opposite the place where the quick throw was taken.
What a lot of people don't realise is that the ball does not have to be thrown in straight, provided it goes back towards that player's goal line.
A quick throw cannot be taken if the ball has been touched after it went into touch by anyone, other than the player throwing in or the player who carried it into touch. This includes touching fences and buildings.
Nor can it be taken with a different ball, or after a lineout has already been formed, when at least two players from each side are lined up on the line-of-touch ready for the ball to be thrown in.
If any of the above are contravened the quick throw is disallowed and the lineout takes place where it would have but for the attempted quick throw.
There are a lot less lineouts these days than when players could kick the ball directly into touch from anywhere on the field and not have to go back to where the kick was taken for the lineout.
But players who are aware of the laws and use them to their advantage can help the speed and continuity of the game and give their team that added momentum that can be the difference between winning and losing a game.