[heart76]

System is 2/1 (or SAYC for what that matters) with Jacoby2NT GF raise by non passed hand.
Suppose they interfere at the 2 level after you open 1M, say 1!S - 2!D.
How do you bid the following hands as responder, both when you have never bid and when you're a passed hand?
- invitational/limit raise
- non invitational/preemptive raise
- NT invitational or to play with a !D stop
- the same without the !D stop

I have had a few "incidents" with more or less occasional experienced partners who have assumed the common placement is that 2NT is natural invitational with !D stop and 3!S is the !S limit raise, while for me 3!S is preemptive, 3!D askes for stop for 3NT (from a passed hand this looks for 14 HCP also), 2NT is the limit raise.
You have to find a place for the 10-11 HCP with !D stop though.

I have also seen someone playing the X of the 2-lev interference as penalty especially green vs red. But this may be a side topic.

Heart76

[Stephen Tu]

Most common without discussion, at least for Americans, is IMO:

Jump raise weak/mixed/non-inv (exact limits vary by partnership, but something less than a lr) , cue = limit raise+, 2nt= natural inv.

Jump raise limit, cue= gf raise, is an older treatment and is rare in my experience. But that's the by the book treatment for SAYC (some sentence in there says comp doesn't change meanings), though most people have never read the pamphlet so in practice I'd assume the more common treatment.

2nt as the limit raise as in Robson-Segal is just very rare and needs explicit discussion.

Without a diamond stop, plus without fit, you should have a hand suited to either a negative double or forcing free bid in a new suit. Don't really need a stopper ask as opener will typically try 3nt with a stop if you don't have a major fit available, and after a neg double you can probe the next round for a stopper.

[hirowla]

Not dissimilar to what is above:

• Cue raise for a limit+ values. Partner should assume an invite and bid accordingly, you bid higher if you have more.
  
• Raise to 2 with 6-9 points, compete to 3 level if you have 4 card support. If you have 5+ card support consider going to game straight away
  
• Pre-emptive raise with 4+ card support by jumping straight to 3.
  
• Invite to NT game with a stopper by bidding 2NT
  
• Not sure without a stopper - maybe a negative double and then bidding their suit asking for a stopper? You might get too high that way though or your negative double might be offshape.

Another slight variation is a jump to the 3 level shows 6-9 with 4 card support, and ignore the 0-5 point hands. I've tried both - got lots of 0-5 point hands playing this method, got lots of 6-9 point hands when I swapped!

Direct penalty doubles are rare these days - best you can do is trap pass and wait for your partner to reopen the bidding.

Regards,

Ian

[fromageGB]

I give up on a natural 2NT when partner opens a major, preferring to distinguish between 3 and 4 card support. This is vital in a competitive sequence, eg when they bid 4m. In general, a 5 card major will tend to double for penalty if responder has 3, but bid on if responder has 4.

I make no distinction between a responder passed hand or not.

Transfers make it easy to show various hands, such as own suit weak or strong, own suit plus poor major support, etc, and transfers start with X and end with a transfer to 2M :

1♠ (2♦) ...
X = transfer to hearts, suggests 5+.
.. Opener completes transfer if he was prepared to pass a weak 5+ hearts hand, or bids on otherwise. If he completes, pass = to play, other bids suggest invitational or better depending on bid and context, eg bid spades to length of fit, raise hearts, 3♦ = GF cue with guard but needing help, and 2NT/3NT is natural, possibly only 4 cards in hearts.
2♥ = transfer to spades, so a full strength raise to 2♠, eg 7-10 hcp and 3 cards.
2♠ = 3 cards up to 6 hcp
2NT = 3 card support and 11+ hcp and forcing (unlimited)
.. certainly inviting double if they bid 3♦
3♣ = natural, forcing if not passed, passable if passed
3♦ = 4+ card support and 9+ hcp, forcing unlimited
3♥ = jump fit, 5 hearts and sufficient spades/strength for a 3♠ contract, insufficient for 4♠, which hand jumps to 4♥
3♠ = 4 cards and less than 9 hcp (which cue bids)
3NT = natural, no more than 2 spades.

[awm]

Sam and I use over 1S-2D:

3D cue = Limit
3H jump shift = gf raise
3S = preemptive (NV) or mixed (V)
2nt natural

Over 1S-2H:

2nt = limit raise
3h = gf raise
3s as above
X = general values, maybe just 4-3 minors if holding a natural 2nt (some natural 2nts pass and others X depending on heart length and honor structure).

[bberris]

With 10-11 pts and three cards in their suit, you should generally pass! Saving 2NT for this hand is silly; stretch to 3NT if you want. 2NT is only right when you make exactly 8 tricks.

So it makes sense to use 2NT artificially, such as 4 card limit + raise.

Passing with three cards in their suit and invitational has been called the cooperative pass; a play on what used to be called the cooperative double.

https://sites.google...ooperative-pass

[awm]

bberris, on 2017-July-29, 20:12, said:

With 10-11 pts and three cards in their suit, you should generally pass! Saving 2NT for this hand is silly; stretch to 3NT if you want. 2NT is only right when you make exactly 8 tricks.

For the most part, defending an opponent's suit undoubled at the two-level when we have game values does not score particularly well. This seems to be true regardless of the form of scoring. While one can certainly construct examples where our game goes down (or where partner declines an invite and our partial fails with their partial also failing)... this is not a reason to decide that we will simply never play game when they overcall a suit that breaks 3-3 between our two hands! Specific examples aside, I don't think the idea of passing with invitational values and only three cards in the opposing suit is a winning strategy. And the expert consensus seems to agree with me (as pointed out in the master solver's club poll even mentioned in the same link).

[nullve]

awm, on 2017-July-30, 06:12, said:

While one can certainly construct examples where our game goes down [...]... this is not a reason to decide that we will simply never play game when they overcall a suit that breaks 3-3 between our two hands!

Overcaller: 13 hcp, 2434
Advancer: 13 hcp, 4234

Auction:

(2♦)-?

Does your argument still apply?

[awm]

nullve, on 2017-July-30, 10:53, said:

Overcaller: 13 hcp, 2434
Advancer: 13 hcp, 4234

Auction:

(2♦)-?

Does your argument still apply?

Sure, in the sense that I would expect a bad result defending on such a hand. Of course we must design our methods around the space available and probably we need to accept this bad result.

The article pointed to suggests that passing is actually *good* in such situations, even if a bid is available, for example passing rather than raising after 1h-2D with 3334 invitational.

Similarly I think giving up a natural 2nt to pass in these auctions is a serious cost. That is not to say you won't occasionally come out ahead, nor that the benefits of artificial 2nt might not outweigh the loss, but I think anyone claiming passing on balanced invite is a net win is very much fooling themselves.