A rugby scrum restarts a rugby game after a minor infringement of the rules. Understand what goes on. Who puts in? How do you win?
Minor infringements of the rules occur from time to time during a game. Examples are "knock on", "forward pass" and "accidently offside".
When this happens and no advantage is gained by the team that didn`t break the rules, the match official stops the game.
The game is then restarted with a scrum
The eight "forwards" from your team (known as the "pack") form the scrum together with the matching forwards from the opposition.
Both packs form up in the same way.
Two props, one on either side of the hooker form the front row.
The hooker binds to both props, having one arm around each prop. Each prop has one arm around the hooker so they are all bound tightly together.
Two locks form the second row. They bind together by putting one arm around each other to pull them close together. Their heads are placed between the hooker and the props at thigh level and their outside arm binds them to the front row.
The number eight is the third or "back row", head between the locks at thigh level and binding to the locks with both arms.
Also in the back row are two flankers, one on each side of the scrum. They actually bind on to the locks in the second row, so it is really a 3-4-1 formation.
For more details of the actual player positions involved in the scrum contest look at the positions of prop, hooker, lock, flanker and number eight in the section on rugby positions.
Your eight forwards bind together tightly in the 3-4-1 formation and crouch facing the opposition goal-line at the point where the scrum is to take place.
The other team does the same. The two bound-together packs are now close and facing each other. On the word of the match official the two packs crash together.
Actually, for a rugby scrum it`s several words!
An alternative method is being trialled in 2012.
Instead of"Pause, Engage" the match official will simply call "Set".
It`s not an order. It indicates the teams may engage when ready.
The heads and necks of the two front rows are meshed together, holding each other up with equal and opposite forces.
There is now one solid mass of opposing bound players with a tunnel between the two opposing groups.
One team caused the scrum. The other team gets the advantage of restarting the game by putting the ball in to the space between the opposing sets of forwards.
The scrumhalf is always the player who puts the ball into the scrum, always at the lefthand side of the team putting in the ball. It`s called "feeding" the scrum.
The team feeding the scrum always has an advantage because it knows the exact moment it`s going to happen and because of the way the scrum is formed which deliberately creates a small advantage.
The way the front rows ar meshed together means the ball always has slightly less distance to travel to the hooker of the team feeding the ball into the scrum.
Once the ball is in the tunnel the hookers use their feet and legs to 'hook' the ball backwards and so win possession of the ball which moves back through the scrum and exits at the rear.
Because of the advantages, the team that puts the ball in usually wins possession. If the other team wins the ball it`s said the ball was won "against the feed" or they have won a "tight head".
Scrummaging is a very "technical" area of the game.
The forwards use their strength, weight and technique to win clean possession and allow the ball to travel smoothly through to the back where it is picked up by the scrum half or number eight.
When the ball is going towards the back of the oppsition side of the scrum your forwards will try to disrupt possession by pushing them off the ball or "wheeling" the scrum (turning it sideways).
The scrumhalf not putting the ball into the scrum may stay near the scrum.
Any other players not part of the scrum must stay behind their offside line which means staying at leat 5 metres behind the back of the scrum.
Law 20 governs the scrum. It is long and complex.
For more information on the basics and a link to full World Rugby information look on this site at rule number 20 in basic rugby rules.