[aguahombre]

1D (1H) X
?

Assuming that the double guarantees exactly four spades.
Assuming that with 4 spades, opener will rebid 2♠(min), or more spades (extras).
Assuming, therefore, that a 1♠ rebid shows only 3 of them:

The question is whether opener, who rebid 1♠ should expect responder to act again unless absolutely minimum for the double (say, 7 or less).

This question was inspired by an "It's Your Call" hand in the ACBL Bulletin. Opener held
AXX KJTX AKXXX Q. The vast majority of experts chose the reasonable-but flawed-2NT rebid.
Only one panelist chose 1♠. It would seem that a final contract of 1S would be fine if responder had a real dog without diamond support and that a 2NT rebid could work out badly. But if responder will keep the auction open with more (8+), then 1♠ feels right.

Those of us whose neg double denies spades would not have the luxury of the choice.

[barmar]

Most play that 1♠ shows 4 spades and minimum (but he might do it with 3 and no other reasonable rebid), 2♠ shows 4 spades and extra (invitational) values. I've never heard of jumping to 2♠ just to confirm a 4-card suit. I just checked a couple of web sites on bidding conventions, and they agree.

However, it's a playable agreement. If there hadn't been any interference, responder would have bid 1♠, and opener would have raised to 2, so it doesn't get you any higher than you would have gotten in an unobstructed auction. But since it's not the way this is usually played, so you'll need to discuss it with your partner; without this discussion, you should assume that a jump rebid shows extras. I also think it would need to be alerted in most jurisdictions, since the opponents will not expect a jump to show a minimum.

[pooltuna]

I play that a one ♠ response shows 3 or a rock bottom minimum with 4 not interested in competing further. But I still expect to compete to whatever is a reasonable level

[aguahombre]

Still waiting for thoughts on the "semi-forcing" nature of 1♠ by anyone willing to accept the assumptions listed. Several pairs do, in fact bid 2 as if raising a response when they have 4 and a minimum. Billy Miller even advocated it in an article. But, I wasn't really looking for a debate on the treatment of 1S showing only 3 --rather more on whether responder should keep the auction open with as few as 8 HCP.

[jogs]

Can you cite the article? Which publication and which month, year did Miller write the article?