There are really eight circumstances when the referee must call the maximum penalty of seven points during a frame of Snooker.
The first and most obvious is if the Black ball is involved in any way in a foul stroke by either being the ball on, the ball concerned or one of the balls struck simultaneously when one of them is not a ball on.
There are seven others which might not necessarily involve the Black ball but are still mandated to receive the highest penalty by the instructions in Section 3 Rule 10 d)
I have listed them here with visual aids for six of them which may make it easier to remember them by. It is important for all referees to be fully conversant with this part of the rule as it is very often a question that will be included in examinations and is also a popular trivia question at other times, but with the main reason being that the rule quoted demands it and if they ever arise during a frame of Snooker the referee must know what penalty to impose.
These rules are, as listed in the rule book: -
7 points if the striker -
d) i) Uses a ball off the table for any purpose.
ii) Uses any object to measure gaps or distance.
iii) Touches any ball during consultation as described in Section 3 Rule 14 g)
iv) Plays at reds, or a free ball followed by a red in successive strokes.
v) Uses any ball other than the white as the cue ball for any stroke after the frame has started.
vi) Fails to declare which ball he is on when requested to do so by the referee.
vii) After potting a red (or a free ball nominated as a red), commits a foul before a colour has been nominated.
There is also a mnemonic that might be useful. In remembering the phrase ‘REF STUNG’ each letter can be used as a lead-in to a key word which will bring that rule to mind. Although not in order (which really doesn’t matter) it goes as follows.
RE – Refusing (failing) to declare when asked.
F – Fouls after potting a red and before nominating.
S – Successive reds (playing at).
T – Touches a ball in consultation as in 14g.
U – Uses a ball off the table (for any purpose).
N – Not the white. i.e. using an object ball as the cue ball.
G – Gaps or distance (using an object to measure either).