What defines an open ball for nine wicket wiring?
An open ball must have at least a full ball width of open space on either side relative to a straight line from the striker ball. This confuses some people as the target ball may be completely visible, but a full shot means a ball could just nick the target ball on a roquet. For example, if a stanchion or dead ball is just an inch a way to the right of the ball the striker is open on, then the shot is not fully open.