When the table is open (for example, always after the break regardless of which colours were potted), the player does not have to nominate their colour group EXCEPT if the choice is not clear, like in a situation illustrated here.
The rules require that to decide groups, the player must pot the colour that they play, which then in turn means that it must be clear to the referee which color group they are playing.
- If the player nominates yellows, plays the yellow and pots the yellow, then colours are decided, they are yellows and they continue with their visit. Similary if they do the same with reds.
- If the player nominates yellows, plays the yellow and pots the red (without also potting a yellow), then this is a ‘loss of turn’ shot and the table remains ‘open’.
- If the player nominates yellows, plays the yellow and pots the red and a yellow, then colours are decided as yellows because combination shots are allowed.
- If the player nominates yellows, and hits the red without potting it, then control of the table passes over to the oponent, because the table was ‘open’ anyway and no foul has been committed.
- If the player nominates yellows, and hits the red and pots it, then this is a standard foul because they are required to pot the colour that they play.
The decision about whether or not the choice was obvious is at the discretion of the referee, so for the avoidance of doubt, making a habit of nominating is not a bad thing. But, unlike the World Rules, if a colour group was potted from the break and that colour group is then nominated, the player is NOT that colour until they legally pot a ball of that group. Nomination does not decide colours, it only makes it clear to the referee what the target colour group is for the next shot.