[Wainfleet]

After 1S-2C-2H what does 3S show? Can partner pass?

I ask because I played a hand on Jack Bridge where Jack reserved the 3S bid to show a 15+ hand with 3 card support, obviously forcing. I lowered responder's strength to 13 points and 3 card support and Jack used Fourth Suit Forcing (to game).
I lowered the strength to 11 points and 3 card support and Jack bid 2S. I would have expected Jack to bid 3S invitational.

[apollo1201]

Hello and welcome

This is extremely system dependent and Jack does not seem to play the same system as you.

In older or simpler systems, 1M-3M is « 11 and 4-cd » so with only 3-cd you need to bid as you did (2m followed by 3M invitational). This way of bidding created difficulties for big fitted hands (especially when opener rebids 2M).

In more modern or advanced systems, this 3M rebid shows a strong slam interest (even 2C could already be a Game Force). Invitational hands bid differently (1NT forcing, or some artificial raise between 2NT and 3M-1). I guess Jack plays this way.

This has then consequences on the « game only » hands as well as the invitational ones. That is why Jack bid them differently (although I am not quite sure to understand why 4SF rather than just 4S with the 13 hand).

There should be somewhere à description of Jack system for you to review?

[johnu]

Wainfleet, on 2025-July-31, 13:49, said:

After 1S-2C-2H what does 3S show? Can partner pass?

I ask because I played a hand on Jack Bridge where Jack reserved the 3S bid to show a 15+ hand with 3 card support, obviously forcing. I lowered responder's strength to 13 points and 3 card support and Jack used Fourth Suit Forcing (to game).
I lowered the strength to 11 points and 3 card support and Jack bid 2S. I would have expected Jack to bid 3S invitational.

Isn't 2♣ already forcing to game? If so, there are no "invitational" bids. Unless Jack plays some kind of system where 2/1 is not game forcing.

[Wainfleet]

Jack allows you to choose your system. There are 10+ pages of settings - I have set it to Modern Acol, 4SF to game. I have used Jack a lot and it is very reliable usually.

[P_Marlowe]

Wainfleet, on 2025-July-31, 13:49, said:

After 1S-2C-2H what does 3S show? Can partner pass?

I ask because I played a hand on Jack Bridge where Jack reserved the 3S bid to show a 15+ hand with 3 card support, obviously forcing. I lowered responder's strength to 13 points and 3 card support and Jack used Fourth Suit Forcing (to game).
I lowered the strength to 11 points and 3 card support and Jack bid 2S. I would have expected Jack to bid 3S invitational.

The first question is, does 2S in the seq.

1S - 2C
2H - 2S

show primary support or could it be based on 2 cards.

If playing Acol, I would assume 2S too be 2 cards and 3S to be inv. raise with 3 cards.

I have not played Acol for over 20 years, i.e. my understanding may be out of sync.