10.1.1 The ball sent to the opponent’s court must go over the net within the crossing space. The crossing space is the part of the vertical plane of the net limited as follows: (Diagram 5, Rule 10.2)
10.1.1.1 below, by the top of the net;
10.1.1.2 at the sides, by the antennae, and their imaginary extension;
10.1.1.3 above, by the ceiling.
10.1.2 The ball, coming from the first hit of the team, that has crossed the net plane to the opponent’s free zone totally or partly through the external space, may be played back within the team hits, provided that:
10.1.2.1 the opponent’s court is not touched by the player;
10.1.2.2 the ball, when played back, crosses the net plane again totally or partly through the external space on the same side of the court.
The opponent team may not prevent such action.
10.1.2.3 the ball, sent to the opponent’s free zone totally or partly through the external space, which has come from the second or third hit of the team, cannot be played back and will be judged as ball OUT the moment it crosses the net plane.
10.1.3 The ball that is heading towards the opponent’s court through the lower space is in play until the moment it has completely crossed the vertical plane of the net.
While crossing the net, the ball may touch it (Rule 10.1.1).
10.3.1 A ball driven into the net may be recovered within the limits of the three team hits (Rule 9.1).
10.3.2 If the ball rips the mesh of the net or tears it down, the rally is cancelled and replayed. (VC Guidelines 2.2)