Be aware that, as with everything to do with Bridge, some players use variations to that described below.
The following is the commonest way to play it.
When Partner opens 1NT bid 2 ♣ Stayman
A 2 ♦ response denies a 4 card Major,
2 ♥ or 2 ♠ shows a four card suit
Responder now bids as follows:
After a 2 ♦ response a re-bid of two of a Major is weak to play
as above.
After a 2 ♦ response a
re-bid of 3 ♦ asks for best 3 card Major.
This caters for 5/5 hands and is usually referred to as Extended Stayman
After a 2 ♥ response a re-bid of 2NT shows balanced 11pts
and denies 4 Spades
After a 2 ♥ response a
re-bid of 2 ♠ shows 4 Spades and 11 points
After a reply in a Major a re-bid of 3 of that Major agrees the suit and shows a 7 loser hand or 11pts .
Invitational only
If the Opener now bids 3NT they will be showing enough points to go to game but completely balanced and
usually most of the points in the other suits.
Responder should only pass with a similar shaped hand
otherwise convert to 4 of the Major.
After a reply of a Major a re-bid of 3NT is 13-15 with the other Major
.
See Stayman after a 2NT Opening
See Simple Transfer Responses to 1NT Opening
See Simple Transfer Responses to 2NT Opening
See Action when opponents interfere with Stayman