Stayman, then 2S

[Gerben42]

So can we then agree on:

 

1nt 2♣ 2♦ 2♥ = weak both majors

1nt 2♣ 2♦ 2♠ = invite 5♠ 4♥

1nt 2♦ 2♥ 2♠ = invite 5♥ 4♠

 

and

 

1nt 2♣ 2♥ 2♠ = invite 4♠ (sequence A)

1nt 2♣ 2♥ 2NT = invite no 4M

(even though there may be better ways as people have suggested, this way is NATURAL and therefore intuitive)

 

FYI I play that sequence A shows either invite with no 4M or slam interest with ♥ fit. But I'm not suggesting that for BBO Advanced...

[cherdano]

I came to the same conclusion Gerben.

[luis]

+1 for Gerben's scheme is simple and natural.

 

Luis