13 = 1 of a suit
16-18 balanced = 1NT
22-24 balanced = 2NT
25-27 balanced = 3NT
25+ = 2 of a suit
RESPONSE TO 1 OF A SUIT
0-5 without trump support = pass
3-9 with trump support = raise by one in the suit
11-13 with trump support = raise by two in the suit
6-10 balanced = 1NT
14-15 balanced = 2NT
16-17 balanced = 3NT
6-9 and wide range = new suit at level 1
10-17 and wide range = new suit at level 2
RESPONSE TO 1NT
0-6 without a long suit = pass
0-6 with a long suit = 2 of a suit
7-9 with a long suit = 3 of a suit
7-8 balanced = 2NT
9-14 balanced = 3NT
15+ = 4NT
After opening of 1NT or 2NT, bid clubs if you have 8 or more high card points.
Then the opener (who originally bid NT) bids for a major four-card suit: If opener has at least four hearts, he/she bids four hearts. If opener has four spades but NOT four hearts, bid spades. If opener does not have four of either, he/she bids diamonds. Opener and partner are trying to match with eight majors.
HEARTS: hearts and perhaps spades
SPADES: only spades
DIAMONDS: no major suit
2NT: unbid four-card major
3 Diamonds or clubs: at least 10 points and a five-card suit. Forces and may lead to a slam opportunity.
3 Hearts or Spades: Four-card support for opener
3NT: sign off to preclude higher bidding
4 Hearts or Spades: sign off and play suit called.
4NT: 14 or more honors points and invitation to pursue a slam.