The Carrot 1NT is a contract bridge convention, in which a 1NT opening bid shows a balanced hand 13-17 hcp. With 13-14 hcp, the opener may not have a 4-card major. With 15-17 hcp, all balanced hands (including 5-card major) may be opened 1NT.
While originally developed for the Carrot Club system, this opening bid can easily be adopted in any system with a 15-17 1NT-opening (or extend a 14-16 1NT-opening to 12-16 hcp).
It combines the preemptive advantage of a weak 1NT-opening when opener lacks majors, with the constructive character of a strong 1NT-opening.
To manage the "wide" hcp-range, a special response-structure has been designed, which distinguishes between weak invitational bids (ca 7-9 hcp, inviting the 15-17 hand only) and strong invitational bids (10-11 hcp, inviting the 13-14 hand and game-forcing to 15-17):
2♥/2♠ are natural weak (7-9) invitations with a 5-card major.2NT is a strong (10-11) invitation, which may also contain 4-card major(s) (opener will only pass with 13-14, in which case he cannot have a 4-card major).2♣ is Stayman on most other hands (7-9 weak invitational, or game-forcing strength) but is also used with a 5-card major and strong invitation, 10-11.2♦ is a relay to 2♥ with sign-off hands or certain game-forcing hands.3♣/♦ are natural invitation to 3NT with a long suit, 6-9. If minimum, the suit should have 2 top honors.3♥/♠ are natural invitation with 6-card suit, 9-11.3NT natural to play.4♣/♦ are transfers to 4♥ and 4♠ ("South African Texas").4♥/♠ natural to play.4NT is Blackwood 4 Aces.If opponents overcall 1NT:
Double is negative, ca 8-11 hcp, and forcing to 2NT (or penalty-double).2 of a suit is constructive to play or possibly mildly invitational.2NT is Lebensohl-style and relay to 3♣. Responder can pass or correct to a suit lower than the overcall (or the suit overcalled, if overcall was artificial)