[yunling]

A few systems use 1S-2D as hearts so 1S-2H includes GF 5+D (some will put other hand types in it which make it more difficult to continue).
e.g. Ambra uses a fairly "normal" follow up so 2S is minimum, 2N/3x is natural and max but opener can't show 5-5/6-4 majors below 3NT, which is losing a lot of major information compared to traditional systems.

Anyone has a good continuation of this auction?

[nullve]

The continuation in Il sistema Bocchi-Duboin looks quite good.

[kreivi68]

I haven't played such a system, but this comes to my mind:

1♠-2♥:

2♠ = min
2NT = extras, majors 5=4/6=4
3♣ = natural, extras
3♦= 3+♦ support (including 18-19 balanced)
3♥ = 5♠+5♥, min/max
3♠ = 6+♠, self-sufficient suit
3NT = 5=3=2=3, 18-19

[glen]

nullve, on 2021-April-16, 09:27, said:

The continuation in Il sistema Bocchi-Duboin looks quite good.

This would be:

2H = 5+D GF (or 6+D invite)
--- 2S = 5+S with either 4+C or 4+H
------- 2N = asks
----------- 3C = 5+S-4+C
--------------- 3D = asks
------------------- 3H = 2524/3514 11-15
------------------- 3S = 2524/3514 16+
------------------- 3N = 5S-5C 11-15
------------------- 4C = 5S-5C 16+
------------------- 4D = 6S-4C 11-15
------------------- 4H = 6S-4C 16+
----------- 3D = 5S-3D
--------------- 3H = asks
------------------- 3S = 4C 11+
------------------- 3N = 4H 11-15
------------------- 4C = 4H 16+
----------- 3H = 5422/5413 11-15
----------- 3S = 5422/5413 16+
----------- 3N = 5S-5H 11-15
----------- 4C = 5S-5H 16+
----------- 4D = 6S-4H 11-15
----------- 4H = 6S-4H 16+
------- 3C = 6+D 9-11 (if you play can be an invite)
------- 3D = 6+D GF
--- 2N = 1-suiter without 3+D
------- 3C = asks
----------- 3D = 6+S UNBAL
----------- 3H = 6+S BAL
----------- 3S = 5323 11-14
----------- 3N = 5323 15-17
----------- 4C/D/H = 6+S, shortness
----------- 4N = 5323 18-19
------- 3D = 6D 9-11 (if you play invite)
------- 3H = 6+D GF
--- 3C = 5S-4D 11+
--- 3D = 5S-5D or 6S-4+D
--- 3H = 5S-3D-(3-2)
--- 3S = 6S-3D 11-14
--- 3N = 6S-3D 15-17
--- 4C = 6S-3D 18+