Pressure occurs when a team goes forward with support making effective tackles and competing for the ball or tackling the player and the ball, to stop the continuity.
If support is not available and the pass is not made, the ball will become contestable as it will have to be played immediately the tackle has been completed.
Therefore, it may be better defence to use a smother tackle to prevent the pass being made in the first place and create an advantage by sending in a second defender so that possession is not regained. The philosophy for the defenders is to form a maul and rely on the "use it or lose it" Law to obtain the put in at the scrum.
Sound judgment is necessary as if a team commits too many to a counter ruck and does not win the turnover they will leave a lot of space for the attacking team. If they have an initial counter ruck and then determine they will not get the turnover, they must be prepared to reform the defensive line very quickly.
Defensively it is important to apply pressure by tackling to prevent a territory gain and to slow the ball down.
The art of tackling in wide open spaces and then attacking the tackle point are valuable arts to have players master in the game of Sevens. Tackling and attacking the ball applies pressure and worst case scenario affects the speed of the recycle for the attacking team. Unstable attacking rucks can be turned over and like all other aspects of the game, accurate decision making is vital. The tackler and one other should carry out these roles.
To ensure the off load in the tackle is not effective the defender from the inside must fill in the space inside the tackler and the defender on the outside of the tackler must have sufficient depth to cover a support runner on the outside shoulder of the attacker by moving in for the tackle. If a normal pass is made the outside defender is in a position to tackle from ‘inside-out’. (Defend in 3’s)
Defence systems in Sevens have evolved. Probably the most common form of defence is a 6 man Jockey system with one player hanging back in the fullback or sweeper role.