Rule

One-wall · Rule 4.8 Avoidable hinders

Failure to move

A player does not move sufficiently to allow his/her opponent his/her shot.

Interpretation

The player standing further from the wall must move out of the way of his opponent even though it may mean moving to an undesirable court position. If a player assumes such a position and there is a collision, or there is interference with the stroke of the player trying to strike the ball, the hinder is avoidable.

Mentioned here

Full One-wall rulebook