when responder holds 5 spades and 4 hearts, some of the responses change: After 2NT-3, opener's 3 denies a 5-card major but promises 4 hearts or 3 or 4 spades. Following this, responder bids: 3 showing a 4-card spade suit, possibly including a 4-card heart suit, or 5 spades and 4 hearts. Opener's rebids: 3 = showing 3 spades and denying 4 hearts, responder now bids 4 with 5S4H, or 3NT otherwise 3NT = showing 4 hearts and denying 4 spades, responder now leaves in NT or converts to 4 with a 4 card heart suit 4 = showing 4 spades. 3 showing a 4-card heart suit and denying a 4-card spade suit, responder converts to 3NT or 4 as appropriate 3NT denying a 4-card major, to play. Checkback Stayman 2 Checkback Stayman (or simply Checkback) is used after a 1NT rebid by opener rather than a 1NT opening. It is used to "check back" if opener has major suit support, saying nothing additional about the club suit. It can find 3-5 fits, 4-4 fits (in Standard American) and 5-3 fits (in Acol), and also shows whether opener was maximum or minimum strength for his notrump bid. In five-card major systems, bidding Checkback implies that the responder has five cards in his major, and may have four in the other. 1m – 1M; 1NT – 2 The 2 is Checkback Stayman. Responses by opener shows the following: 2: No three-card support for partner's major, no four-card holding in the other major and a minimum hand. 2/: Bidding responder's major shows three-card support and a minimum hand; bidding the other major shows four cards and a minimum hand. 2NT: No three-card support for partner's major, no four-card holding in the other major and a maximum hand. 3/: Bidding responder's major shows three-card support and a maximum hand; bidding the other major shows four cards and a maximum hand. Partnership agreement is required on how to handle the case of holding four of the other major and three of partner's suit. One could agree to bid up the line, or support partner's suit first. If partner cannot support your first suit, he will invite with 2NT or bid game with 3NT and you will then correct to your other suit. In Acol, if the opening bid was a major, opener can rebid his major after a Checkback inquiry to show that it