When do I call a let or interrupt play?

You decide each rally as a point or a let (ITTF Statutes 2026, regulation 3.3.2.3.6). Under Law 2.9 the rally is a let if:

• in service, the ball touches the net assembly, provided the service is otherwise correct or the ball is obstructed by the receiver or partner;
• the service is delivered when the receiver isn't ready, provided neither the receiver nor partner attempts to strike the ball;
• failure to make a service or return, or otherwise comply with the Laws, is due to a disturbance outside the player's control;
• play is interrupted by the umpire or assistant umpire; or
• the receiver is in a wheelchair and an otherwise correct service, after touching the receiver's court, returns towards the net, comes to rest on the receiver's court, or (in singles) leaves the receiver's court over a sideline.

You may interrupt play:

• to correct an error in the order of serving, receiving or ends;
• to introduce the expedite system;
• to warn or penalise a player or adviser; or
• because conditions of play are disturbed in a way that could affect the outcome of the rally.

Either you or the assistant umpire may decide that, in an otherwise correct service, the ball touched the net assembly, and that the conditions of play are disturbed. A ball touching the net assembly during a rally after a return is still in play.