[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.

[AL78]

I play it as invitational with three card support but I am used to Acol. I suspect most people on here play 5CM or some system where it is a game force raise.

[pescetom]

Playing modern 5 card majors, the 2C response was already a game force, now 3S fixes trumps in spades and requests a control-bid. A jump to 4S is a negative "fast arrival", denying any lateral controls or perhaps apologising for a sub-strength opening. 3NT may be "non-serious" denying slam interest in a different way (perhaps specifically about trump suit quality).

I don't like Jack's reported choice to bid 4SF with fit and I find the failure to invite with 11 incomprehensible.

[johnu]

This is a duplicate question from the Novice and Beginner forum. In that other post, you clarified that Jack is playing Modern Acol.

As to Jack playing a jump to 3♠ as 15+ points, that's just the way Jack implements their Acol system. You might as well complain about the way GIB plays. Actually, complaining to Jack developers may get a response, rather than going into the black hole where complaints about GIB are filed.

[smerriman]

johnu, on 2025-August-02, 17:51, said:

Actually, complaining to Jack developers may get a response, rather than going into the black hole where complaints about GIB are filed.

Really? As far as I'm aware, Jack was last updated in 2015 - abandoned well before GIB was.