[mike777]

Team game
1C=(1H)=X=(P)
?

Opener now rebids 1S or 2S
What do you expect?

[apollo1201]

Assuming X shows a 4 cd S, let s make as if partner had bid 1S.

Then 2S is a fit with 4 cd S and minium (12-14 presumably), and all other calls also like when partner bids 1S.

The only call that remains (besides the rare conversion to penalty) is 1S that can be played as a 3 cd fit not willing to bid 1NT or 2C. Picture something like Kxx xx AQx Kxxxx. Could be played as forcing or not. Up to agreement.

[DavidKok]

There are two styles here.

The classical style is to reserve the 1♠ response for hands with 4 spades, confirming the hand cheaply. The jump rebid of 2♠ then shows 4 spades and a stronger hand.
The modern style is to bid 2♠ with 4 spades even with a minimum, reasoning that we are never going to buy the contract at the 1-level anyway with an 8-card fit. This means invitational hands have to make a stronger bid than 2♠ (e.g. 3♠ or 2♥), and it frees up the 1♠ response for hands with only 3-card support. I've only ever played this 1♠ NF, as I'm a bid worried having to show 3-card support with a strong unbalanced or semibalanced hand and then getting pushed out of the bidding by overcaller's next bid, but you could also make this wide ranging.

P.S.: Some people play the double here as a sort of transfer, showing 4-5 spades rather than the traditional 'exactly 4'. In that case clarifying whether you have 3-card support or not becomes more important, and a forcing 1♠ rebid might be more valuable.

[fuzzyquack]

Expert's agreement is that 1♠ response may contain good but not GF (in the context) hands that can't commit to NT, e.g. Kxx,xx,AQJ,AKJxx or Kxx,x,AQxx,AKxxx. Bidding 2♥ with the first hand is likely to create a mess whilst with the second you don't have enough to reverse and show the ♠ fragment later. Educated partner should rarely pass 1♠.

[DavidKok]

I don't think this is a common agreement at all, and I highly recommend not springing this on partner without discussion.

[mikeh]

 fuzzyquack, on 2024-November-06, 01:55, said:

Expert's agreement is that 1♠ response may contain good but not GF (in the context) hands that can't commit to NT, e.g. Kxx,xx,AQJ,AKJxx or Kxx,x,AQxx,AKxxx. Bidding 2♥ with the first hand is likely to create a mess whilst with the second you don't have enough to reverse and show the ♠ fragment later. Educated partner should rarely pass 1♠.

You know different experts than do I if you think this is an expert treatment, let alone a playable approach.

If I had to assert any ‘expert agreement’ it would be the increasingly popular treatment referenced by David: the double of 1H, after a 1m opening, shows 4-5 spades, and this fits extremely well with opener’s 1S showing 3 spades and 2S showing a 4 card minimum. Fwiw, I play this in my main partnership and have for several years.

The usual corollary to this meaning of double is the use of 1m (1H) 2H to show my hand with 6+ spades. I didn’t study how many pairs played the ‘x=4-5 spades’ at the recent WC in BA, but (after losing the quarterfinals in the seniors….to a team from India that played as flawlessly as I seen anyone play) I did watch a fair bit of vugraph and virtually all doubles of 1H overcalls (not that there were many such auctions) were explained as 4-5….. my take on this is that the treatment is bearing ‘standard’ status at the highest levels of the game for those playing naturally based methods, and iirc those playing such methods as Meckwell lite.

[bluenikki]

 mike777, on 2024-November-04, 15:07, said:

Team game
1C=(1H)=X=(P)
?

Opener now rebids 1S or 2S
What do you expect?

In the 1972 notes for Kaplan-Sheinwold, the auction 1♣ - (1♥ ) - X - (P) ; 1♠ says "I would have felt like passing had you responded 1 ♠." Useless hearts, or 3 spades. Sounds right to me. But this is in a system where opener has 15+ if balanced. So I visualize

xxx
xxxx
A
AKxxx

[bluenikki]

 mike777, on 2024-November-04, 15:07, said:

Team game
1C=(1H)=X=(P)
?

Opener now rebids 1S or 2S
What do you expect?

In the 1972 notes for Kaplan-Sheinwold, the auction 1♣ - (1♥ ) - X - (P) ; 1♠ says "I would have felt like passing had you responded 1 ♠." Useless hearts, or 3 spades. Sounds right to me. But this is in a system where opener has 15+ if balanced. So I visualize

xxx
xxxx
A
AKxxx

[mike777]

Fwiw watching Zia at
Imps.
Partner made negative double.
Zia responded one spade with 4Spades and balanced 14 count.

Bit surprised that not one kibitzer chimed in..

They eventually ended up in 3 spades making 4 on borderline vul game.