Tackling is the only way of legally bringing down your opponent in rugby union.
But there are certain laws on how to tackle and if these are not adhered to, penalties will follow.
When you tackle an opponent, you cannot make contact above the shoulders. This is for safety reasons.
The referee will instantly give a penalty if he sees a high tackle, and a few stronger words may follow if the challenge is deemed dangerous.
Expect a yellow card and a spell in the sin-bin or a red card and instant dismissal for more serious offences.
Other laws govern what can and cannot happen once a tackle has been made.
GOING TO GROUND
Once a player in possession of the ball has been brought to ground by a tackler, they must release the ball immediately.
They can do this either by passing off to a team-mate or placing the ball on the ground.
The tackler must release the player they have just brought down and roll away from them and the ball.
If the referee believes the tackler has not rolled away quick enough, he will award a penalty to the opposition.
The same is true for the player who has been tackled. If they do not release the ball immediately and roll away from it, they will concede a penalty.
Referees are strict on this, because players can often try to slow the ball up for the opposition, helping their side to re-group in defence.
STEALING BALL IN THE TACKLE
If they are quick enough, a team-mate of the tackler can pick up the ball from the contact area as long as they are on their feet.
However as soon as a team-mate from the ball carrier's side comes into contact with that player and the ball is still on the ground, the tackle then becomes a ruck.
None of the tackler's team-mates can attempt to handle or pick up the ball once the ruck has formed.
However they can use their strength to drive over the team in possession and attempt to win the ball.
If a player has been tackled and their natural momentum takes them over the try-line and the ball is grounded, a try is awarded.
A player tackled near the goal-line can also reach out and attempt to touch the ball down for a try.
There are certain situations where tackles cannot be made.
If the ball carrier has been held by an opponent, but has not gone to ground, and a team-mate has bound onto them, a maul is formed.
At that point a tackle cannot be made for safety reasons.