bixby, on 2019-July-07, 03:51, said:
In an ACBL regional event yesterday, North opened 2NT with a small singleton club. I don't know what he was planning to do if South bid 3NT -- presumably pass and take his chances. As it happened, N/S got to 4S making 6 for a slightly below-average score. Almost everyone was in the same contract. A few pairs reached the slam, doubled E/W in 5C, or, sadly I'm sure, played it in 1D.
Is the 2NT opening bid legal in the ACBL? If not, what would the ruling be?
Which of the four convention charts was in effect? If you don't know that, what kind of event was it? Was there a masterpoint limit?
For a Regional, the following charts apply:
Pair Events and non-Bracketed Team Events
Basic Chart:
Applies in any event where the upper limit per player is 750 or less.
Basic+ Chart:
Applies in any event where the upper limit per player is 3000.
Open Chart:
● applies in any 1-session event with no masterpoint limit (includes Side Series);
● applies in any restricted event with a masterpoint limit above 3000;
● applies in any 2-session event with no masterpoint limit if there is no 2- session event of the same type with a masterpoint limit on the same day
Open+ Chart
● applies in any 3+-session event with no masterpoint limit;
● applies in any 2-session event with no masterpoint limit as long as there is a 2-session event of the same type with a masterpoint limit on the same day
Bracketed Events
A single bracket event always uses the Open Chart.
For bracketed events with more than one bracket, the Open Chart is used in most brackets with these exceptions:
Basic Chart: Any bracket where the highest team averages less than 750 masterpoints per player;
Basic+ Chart: Any bracket where the highest team averages 751 to 1500 masterpoints per player;
Open+ Chart: Top bracket (regardless of team masterpoint holdings), and any other bracket where the lowest team averages more than 3000 masterpoints per player.
In all types of events, when the directors allow a team to play in a higher bracket than its masterpoint holding would qualify the team for, that team’s masterpoint total is ignored in determining which Chart applies.
As Hrothgar points out, a partnership understanding to make this opening is legal
unless the basic chart governs the event. Whether this particular opening is legal when the basic chart governs depends on whether the pair has an (explicit or implicit) agreement to open 2NT with hands like this. One hand is not sufficient to answer this question, the director will have to investigate.
If the pair are determined to have an illegal agreement,
Law 40B4 applies:
When a side is damaged by an opponent’s use of a special partnership understanding that does not comply with the regulations governing the tournament the score shall be adjusted. A side in breach of those regulations may be subject to a procedural penalty.