6.11 Bad Play from Behind the Head String

When the cue ball is in hand behind the head string, and the first ball the cue ball contacts is also behind the head string, the shot is a foul unless the cue ball crosses the head string before that contact. If such a shot is intentional, it is unsportsmanlike conduct.
The cue ball must either cross the head string or contact a ball in front of or on the head string or the shot is a foul, and the cue ball is in hand for the following player according to the rules of the specific game.