A scrum is a restart, not a union-style contest.

When a scrum is used

A scrum is used only when that is the correct restart for the phase. The most familiar examples are accidental knock-ons and forward passes. If the ball is dropped forward, passed forward by mistake, or lost after a completed tackle in a way that requires a stoppage, the referee usually restarts with a scrum for the non-offending team.

The important limit is the tackle count. If an accidental breach or the ball going into touch happens after the fifth play-the-ball, the usual outcome is a handover rather than a scrum. Rugby league does not give the attacking team another set just because the final-tackle error would otherwise have been a scrum offence.

When play restarts another way

Many stoppages that look like "scrum situations" to new viewers are restarted in other ways. Current international laws use play-the-ball restarts for ordinary touch in most cases, tap restarts for successful 40-20 and 20-40 kicks, free kicks after a penalty kick finds touch, and drop-outs or kick-offs for the restart situations covered by those sections.

• A ball into touch in ordinary general play is not automatically a scrum under current international law.
• A penalty kick into touch is followed by a free kick, not a scrum feed.
• A 40-20 or 20-40 gives the kicking team a tap restart when all conditions are met.
• A last-tackle error that would normally produce a scrum usually becomes a handover.

Who gets the ball

The team that did not commit the offence normally gets the loose head and put-in. In plain terms, that team feeds the scrum and is expected to come away with the ball if the scrum is formed and played correctly.

The halfback feeds the ball from the referee's side, using both hands and without undue delay. After putting the ball in, the halfback must retire behind their own pack, although the laws allow practical movement where the ball has been correctly scrummaged and the player is genuinely retiring.

How the scrum is formed

A full rugby league scrum uses six forwards from each team in a 3-2-1 shape: three in the front row, two in the second row, and one loose forward behind them. The front rows interlock to create a clear tunnel, the hookers bind over their props, and the other forwards pack behind in the required shape.

If a team is depleted, the laws allow reduced packs, but there should still be at least three forwards packing down. Players must remain in the scrum until the ball is out, and no extra player may add weight once the ball has been put in.

When the ball is back in play

The ball is not simply live the moment it is rolled in. It must be scrummaged and emerge correctly, generally from between and behind the inner feet of the second-row forwards. Until that happens, forwards in the scrum may play the ball only with their feet.

If the ball does not come out correctly and the referee cannot blame one team, the scrum can be fed again. If a team deliberately locks the ball in, collapses the scrum, delays formation, detaches illegally, or handles the ball before it is out, the referee can penalise the offence or apply the scrum-specific restart option allowed by the laws.

Where backs must stand

Scrums create a temporary offside line. The opposing scrum half who does not have the put-in must retire immediately behind their own last row of forwards. Other players outside the scrum, apart from the scrum half putting the ball in, must stay at least five metres behind the last row of their own forwards until the ball emerges correctly.

This is why a scrum can create attacking space even when the feed is not heavily contested. The defenders are held behind the scrum line, so the attacking side can choose a set move, shift the ball quickly, or run from a more organised shape.

Where the scrum is set

A scrum is normally formed where the breach happened, but it cannot be set too close to touch or the goal line. Under current international law, the team with the loose head and feed may also choose, within the allowed time, to move the scrum to one of the permitted positions in line with the original infringement: 10 metres in from touch, 20 metres in from touch, or centre field.

That option matters tactically. Moving the scrum can open the short side, create more room for a backline move, or avoid restarting play in a cramped channel near touch.

How referees manage scrums

Officials first identify why play stopped and whether a scrum is actually the right restart. They then mark the location, manage any choice of scrum position, wait for the packs to form correctly, check offside lines for backs, and watch the feed, strike, detachment, and emergence of the ball.

Referees do not treat every messy scrum as the same offence. They distinguish between a technical problem that needs a reset, an accidental problem that means the ball should be fed again, and deliberate conduct such as delay, early detachment, offside backs, collapsing, locking the ball in, or misconduct.

Where people get caught

• "Every ball into touch means a scrum": not under current international law. Ordinary touch restarts are commonly play-the-ball restarts, while 40-20 and 20-40 kicks use tap restarts.
• "A scrum is always awarded after a knock-on": not if the non-offending team gains advantage, possession changes for a zero tackle, or the breach happens in a last-tackle handover situation.
• "League scrums are just ceremonial": no. They are less contest-heavy than union scrums, but formation, offside, feed, delay, and ball-out rules still affect possession and space.
• "The feeding team can choose any spot": no. The laws limit where the scrum can be moved and tie the choice to the original point of infringement.

How to read the restart

1. Ask why play stopped: knock-on, forward pass, touch, last-tackle error, penalty sequence, accidental interference, or another stoppage.
2. Check whether the law calls for a scrum or another restart such as a handover, play-the-ball, tap, free kick, penalty, kick-off, or drop-out.
3. If it is a scrum, identify the non-offending team and give that side loose head and feed.
4. Set the scrum at the correct mark or permitted chosen position.
5. Keep backs behind the scrum offside line until the ball emerges correctly.

Source material

• International Rugby League
• Rugby Football League Laws of the Game
• NRL rules and interpretations