1NT FOR 5 CARDS MAJOR ♠ ♥ ♦ ♣

This adapted 1NT opening uses the Barrelled Stayman conventions also known as Two Way Stayman where 2♣ is a Stayman not forcing and 2is game force.
 
 This convention is mostly used with weak 1nt 13-15 hcp but may also be used with strong nt opening. Let’s assume that our 1nt opening is 15-17 hcp and the allowed distribution are: 4333, 4432, 5332 so it is not recommended the open of 1nt with 5422.
 
 The advantage of this convention is allow the opening of 1nt with 5 cards major and also know when Opener has a 5 card minor.
 
 The drawback in this convention is not to use transfers at level 2 to make the strong hand be the declarer.
 
  Opener Responder (action without interference)
   1NT       pass <= 7 or less hcp (exclude 6/7 cards suit)    
              2
♣ <= Two Way Stayman - not forcing asks for major
                        Opener bids:
                        2
♦ <= no major;
                        2
♥ <= 4♥/5♥ cards in Hearts - can also have 4♠ cards;
                        2
♠ <= 4♠/5♠ cards denies 4♥
                        Responder can pass in 2
♦ or he bids sign-off in 2♥ or 2♠    
              2
♦ <= Two Way Stayman GF with 10+ hcp
                         Opener bids:
                         2
♥ <= 4♥ cards and may have 4♠ cards;
                         2
♠ <= 4♠ cards;
                        2NT <= 4
♣ + 4
♦ have both minors
                                3
♣ by Responder asks distribution
                                Opener bids:
                                3
♥ => 2♠+3♥+4
♦+4♣ or
                                3
♠ = 3♠+3♥+4
♦+4♣  
                                     Responder decide: 3ST / 5 in a minor / try Slam
                         3
♣ <= 5♣ cards
                         3
♦ <= 5♦ cards
                         3
♥ <= 5♥ cards
                         3
♠ <= 5♠ cards
                       3NT <= 4333 distribution with one minor suit
              2
♥ <= to play - sign-off (there are no transfer)
              2
♠ <= to play - sign-off
             2NT <= invitation to 3ST showing 8-9 hcp
              3
♣ <= 5♣-4
♦ with 10-14 hcp in 5431 distribution
                         Opener bids:
                         3
♦ relay asking for the singleton
                              Responder bids up the line:
                              3
♥ => singleton ♥
                              3
♠ => singleton ♠
                              4
♣ => singleton ♥with 6♣4
♦2♠1♥ max 5+ controls
                              4
♦ => singleton ♥with 6♣4♦2♥1♠ max 5+ controls
                              4
♥ => singleton ♥with 5
♦5♣2♠1♥ max 5+ controls
                              4
♠ => singleton ♠with 5
♦5♣2♥1♠ max 5+ controls
                         3NT to play - good stoppers in majors      
              3
♦ <= 5♦-4♣ with 10-14 hcp in 5431 distribution
                         Opener bids:
                         3
♥ relay asking for the singleton
                              Responder bids up the line:
                              3
♠ => singleton ♥
                             3NT => singleton
♠
                              4
♣ => singleton ♥ with 6
♦4♣2♠1♥ max 5+ controls
                              4
♦ => singleton ♠with 6♦4♣2♥1♠ max 5+ controls
                              4
♥ => singleton ♥with 5
♦5♣21♥ max 5+ controls
                              4
♠ => singleton ♠with 5
♦5♣2♥1♠ max 5+ controls
                          3NT to play - good stoppers in majors     
              3
♥ <= 5♥ cards and asks for support -
                         Opener bids 3nt with 2
♥
                         Opener bids 4
♥ without a top honor or minimum 15 hcp
                         Opener cuebid (3
♠/4♣/4
♦) with a top honor and 16-17 hcp
              3
♠ <= 5♠ cards and asks for support -
                         Opener bids 3NT with 2
♠
                         Opener bids 4
♠ without a top honor or minimum 15 hcp
                         Opener cuebid (4
♣/4
♦/4♥) with a top honor and 16-17 hcp
            3NT <= to play
                        Responder may continue bidding his singleton with specials
                        distribution 6-4 bidding 4
♣ or 4or in 5-5 bidding 4♥ or 4♠
              4
♣ <= Gerber - asks for aces (4=0/4; 4♥=1; 4♠=2; 4nt=3)
              4
<= 6♥+ cards Transfer for 4♥ sign-off
              4
♥ <= 6♠+ cards Transfer for 4♠ sign-off
              4
♠ <= 6♣+ cards Transfer for 5♣ sign-off
              5
♣ <= 6+ cards Transfer for 5sign-off  
            4NT <= quantitative - invitation to 6nt with maximum
            5NT <= quantitative - invitation to 7nt with maximum 
                         maximum means 17 hcp or 16 hcp with 5332
                         with 4333 distribution 17 hcp is minimum
 
 In case of interference the partnership need a convention to establish when Responder bids sign-off or is trying to find fit in a major for game.
 Suggestion
Lebensohl. 
 After a 1NT opening and a penalty double we may use:
 pass => nothing to do but Opener having a 5 cards suit must bid it
 redouble => asks for Opener bid 2
♣ and that may be corrected to 2
 2
♣ => Stayman - shows both majors
 2
=> transfer to 2♥
 2
♥ => transfer to 2♠
 
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