New ACBL Policy for 1NT Openings.
The ACBL has changed its policy regarding opening 1NT with a singleton.
From the ACBL website:
Here is the new definition, effective Aug. 1:
“A notrump opening or overcall is natural if, by agreement, it contains no void, at most one singleton which must be the A, K or Q and no more than two doubletons. If the hand contains a singleton, it may have no doubleton.”
This includes hand patterns such as 5-4-3-1, 6-3-3-1 and 4-4-4-1, in addition to those that were previously allowed, such as 4-3-3-3, 5-3-3-2 and 5-4-2-2.
You can read the whole explanation here.
No guidance yet on possible changes to the Alert/Announcement procedure for 1NT openings.