[Siegmund]

Had the same situation come up twice in a sectional pairs today (context is basic 2/1 with a good but unfamiliar partner, no explicit agreements here beyond "negative to 4H" and not playing negative free bids):

1D-(1S)-X-(P)-2H-(2S)-3C

If you are sufficiently old-fashioned, this sequence shows a long weak club suit, as an unconstested 1M-1NTF-2M-3C would.

If you are of the "negative doubles promise 4 of the other major, period" school, which is a common viewpoint on the forum -- A) What does 3C mean here, and B) if it has some fancy forcing meaning, for instance a game try in hearts, do you have any way to show the 7-10 club hand here, or is there nothing between a one-round-forcing 2C and a weak jump?

[whereagles]

Some play 2NT here as a merely competive hand. In that setting 3C and 3H now show genuinely good invites.

[aguahombre]

whereagles, on 2012-February-12, 09:59, said:

Some play 2NT here as a merely competive hand. In that setting 3C and 3H now show genuinely good invites.

We need to do that with 2NT and 3C in this situation; but, only because a direct 2C over 1S would have been game-forcing. I don't think the vast majority who use 1D-(1S)-2C with good invites would need the neg double, then 3C to show that same hand after opener rebids 2H.

So, after:
1D-(1S)-X-(P)
2H-(2S)-?......2N might be weak with diamonds and hearts, 3D invite with diamonds and hearts, 3H just vanilla invite, 3C weak with 4H and longer clubs or whatever.

Would prefer to leave a second double when the same opponent has bid twice in front of me to be penalty.

[Zelandakh]

For me the double promises hearts so 3♣ is a game try, (almost) exactly the same as 1♦ - 1♥; 2♥ - 3♣. To show a weaker hand with clubs you have to either pass or bid 1NT initially.

[whereagles]

aqua, I'm not sure I follow you, but there's an important point that needs to be made here: responder, holding 5+ clubs and 4 hearts, probably needs to make a negative dbl (not bid 2♣) most of the time. Reason: his LHO may raise to 3S. If he hasn't shown 4 hearts by then, he might get stuck for a bid if it comes back to him at that level.

[aguahombre]

whereagles, on 2012-February-13, 07:40, said:

aqua, I'm not sure I follow you, but there's an important point that needs to be made here: responder, holding 5+ clubs and 4 hearts, probably needs to make a negative dbl (not bid 2♣) most of the time. Reason: his LHO may raise to 3S. If he hasn't shown 4 hearts by then, he might get stuck for a bid if it comes back to him at that level.

I think what you are missing is that, in this case, Opener has shown 4 hearts and a minimum by rebidding 2H, so responder no longer needs 3C to show 4-5 in the rounded suits as a strain search. Our only concern would be level.