Quite a lot of time during a game of rugby is spent in and around scrums.
This facet of play is one of the distinguishing features of rugby compared with other large ball games.
The only other game that has a similar ritual is rugby league, and their idea of a scrum is often thought of as a joke when compared to union.
Or is it? In both sports, the scrum is simply a means to restart play after a minor infringement by one team.
The league scrum differs from that of union by having only six players compared with eight.
There are no flankers to harass the opposing halfback or inside backs in league.
The other major difference between scrums in both sports is that the league scrum is usually over in a heartbeat, compared with those in rugby. Why is that?
As part of the joke, the league halfback is allowed to put the ball in under the feet of the second-row players in the scrum.
This ensures their team wins the ball because the other team have no chance of competing for it, going in and out of a scrum within a second or two.
One of the annoying things in rugby is the way scrums often end with a penalty awarded to one team or the other, but usually to the team putting the ball in.
This is especially true in rugby at higher levels, which are often televised.
Once a team's scrum gains a dominance over the other forward pack, we are in for a succession of scrums that don't get completed before the referee blows his whistle.
There aren't actually too many reasons for penalising at a scrum, but one in particular often puzzles the spectators or viewers.
Once the ball leaves the halfback's hands, play in the scrum begins and both teams may push in an effort to win the ball.
In an ideal world, the front row players of the team throwing the ball in should hook the ball to the back of the scrum, where either the back-row player or the halfback should pick it up and either pass the ball or run with it.
The trouble is with clause 19 in scrum law – "players may push, provided they do so straight and parallel to the ground".
This sentence was not in the law book until relatively recently, probably 2018.
Since then, I have been puzzled by referee calls of teams "pulling back" and "standing up under pressure."
Nowhere in the law book is there reference to either of those calls. So why are teams that don't win the ball at scrums being penalised for doing these things?
The team not winning the ball is being penalised for not pushing straight and parallel to the ground.
This may be because the other team's scrum is bigger, stronger and technically superior, and are thus able to exert extreme pressure, so the opposition scrum is no longer able to push straight and parallel to the ground.
So why not say "you're not pushing straight and parallel to the ground" instead of the calls I referred to earlier?
The other questions that arise are why are the players "standing up" or "pulling back?
It could be one or more of the reasons mentioned earlier, but sometimes there are other reasons which are not legal and are often missed by referees because they are blinded by the overpowering play of the dominant scrum.
The answer is not found under scrum law but rather in Law 9, which deals with Foul Play.
Dangerous Play in a scrum is a list of four actions considered dangerous.
Front row players must not form up from a distance from their opponents and then rush against them – this I have yet to see in over 50 years of officiating.
A front row player must not pull an opponent – this also is rare but could include a front row player holding or pulling in an opposing flanker.
Front row players cannot intentionally collapse a scrum, which is also rare but can happen when they are trying to stop the opponents pushing them backwards, especially if they have initially won the ball.
But the critical one is "a front row player must not intentionally lift an opponent off his feet or force an opponent upwards out of the scrum".
This is a hard one for referees to judge, but in my opinion, it is often the reason opposing players "stand up" in a scrum.
The pressure which a dominant scrum is exerting over their opponents can be because the dominant team's front row players are illegally forcing their opponents upwards.
I have seen it demonstrated in scrum workshops by wily props.
I have also heard those props tell referees to let the front row players sort out the scrum situation themselves, because they know what they are doing (and by implication, the referee doesn't.)
So, have a good look at rugby scrums on tv – you usually get slow motion replays – and see if you can judge who is at fault when a team gets penalised before a scrum is completed.
Is the front row "standing up" or "pulling back" because they can't push straight and parallel to the ground, or are they the victims of dangerous actions by their opponents?
Or you could give up and watch the league.