Constructive Raise

~A raise of partner’s opening major to the 2-level shows 3-4 trumps and 8-10 Total Points (Constructive Raise).
~The sequence 1 major-1NT, 2 of a lower-ranking suit, then 2 of opener’s major suit shows that responder either does not have 8-10 points or does not hold 3 cards in partner’s major.
~A jump in partner’s opening major shows 4+ trumps and 11-12 total points.
~With 13+ points and 4+ cards in partner’s opening major, you have the option of a 2/1 game-forcing raise (holding a 5-card side suit) or either of two slam-invites, Jacoby 2NT or a Splinter Bid.
~3NT may be used over 1 major to show a special holding:
~~13+ HCP plus 3-3-3-4 shape with exactly three trumps.
Opener can decide where to play the contract. This jump to 3NT should
be made on about 13-16 HCP.

Opener
S AJT75
H T4
D KJ32
C A6

Responder hand #1
S K43                      1S-1NT, 2D-2S
H K97
D T98
C J432

Responder hand #2
S K43                      1S-2S
H K97
D T98
C Q432

Responder hand #3
S K432                    1S-2S
H K972
D T
C J432

Responder hand #4
S K4                        1S-1NT, 2D-2S
H K97
D T98
C Q543

Responder hand #5
S K43                      1S-1NT, 2C-3S or (SA): 1S-3S
H K97
D A98
C Q543

Responder hand #6
S KT43                    1S-4D (Splinter)
H K973
D AQ98
C Q