[JLilly]

Is there a standard treatment of how responder to an opening of 1M who would normally bid Jacoby 2NT bids if RHO doubles?

[Zelandakh]

Jacoby is usually off after a double and replaced with the Jordan 2NT. This also shows a good raise but now the bottom end is lower, also encompassing invitational (limit raise) hands.

[ggwhiz]

It is very rare to have slam ambitions instead of just game but at unfavourable vul you might run into something like

1♥ - dbl - ? - 4♠ and partner needs a clue when you do NOT have the jacoby 2nt hand as well.

? = 2nt - limit raise or better if partner signs off any bid you make is a game force and you can make slam tries if you have that rare hand
2♥ - just a normal raise, say 6-9
3♥ - all offence, no defence
4♥ - weak(ish depending on the vul) or shapely tending to be + on offence, - on defence

There are variations on this (fit jumps or Bergen raises on) but if the auction heats up partner needs the best clues you can offer as to whether to bid, pass or double.

[fromageGB]

I think my approach is common, and that is "ignore the double". Bid 2NT.

You probably have a very well-defined map of raises and specific meanings when unopposed, so why bother to remember something different and inferior over a double? My 2NT (or rather 2M+1 in my case) is 13+, 4 card support, and partner knows where we are going.

I expect the reasoning for a different bid is that it is not often do you have that hand after a double, so you could have a different use. My argument would be that (a) when you have that hand, partner needs to know it, and (b) there are no gaps in our standard methods (that occur to me) that could be plugged by having another bid.

[Vampyr]

fromageGB, on 2017-January-18, 05:29, said:

I think my approach is common, and that is "ignore the double". Bid 2NT.

You probably have a very well-defined map of raises and specific meanings when unopposed, so why bother to remember something different and inferior over a double? My 2NT (or rather 2M+1 in my case) is 13+, 4 card support, and partner knows where we are going.

I expect the reasoning for a different bid is that it is not often do you have that hand after a double, so you could have a different use. My argument would be that (a) when you have that hand, partner needs to know it, and (b) there are no gaps in our standard methods (that occur to me) that could be plugged by having another bid.

I don't think your approach is common at all. I have never heard of it.

I think that most of you bids can be put to better use once the auction becomes competitive. I feel that Jordan/Truscott is essential, in fact second in importance to the takeout double as far as conventions are concerned.

For example, suppose you play limit raises in an unopposed auction. Once the opponents are involved, don't you want to use up their bidfing space? And jump shifts -- no matter how you play them, fit or weak jumps will help partner judge later in the auction. Bergen etc not reall needed; you have a lot of ways to raise, especially if you play transfers.

[fromageGB]

I was thinking more of the 2NT bid, which concerned the OP, where 13+ is more of a deterrent than Jordan's 10/11+ anyway. With other hands, such as your limit raise, is it better to bid Jordan 2NT rather than 3M-2, which is slightly more preemptive? Is a fit jump really more useful than a splinter, which is probably more likely on the double? I can see you may agree that the rigours of a new suit 2/1 could be usefully shaded a couple of points, or say that these also imply major support, but I do not see the need to abandon your 2NT.

Rather than expanding the meaning of one bid to encompass wider ranges of strength and content, putting opener into a hopeless position if third seat actually bids, why not keep your tighter definitions so that partner knows what to do when put under pressure?

[barmar]

fromageGB, on 2017-January-20, 06:50, said:

Rather than expanding the meaning of one bid to encompass wider ranges of strength and content, putting opener into a hopeless position if third seat actually bids, why not keep your tighter definitions so that partner knows what to do when put under pressure?

Why is it a problem? If opener has enough to accept the invitation, he bids game. If not, he bids 3M if possible, otherwise passes. Then, if responder has extras, he can raise opener to game.

I generally play that Jordan 2NT promises 4+ trumps, like a normal limit raise. If I have only 3-card support, I start with a redouble and raise on the next round.

[Vampyr]

I think that also, as fromageGB notes, it is a question of frequency. Also if 2NT is GF, what do you do with an invitational hand? Maybe 3M -1? Bergen raises?

[fromageGB]

How is it a problem? A correspondent noted earlier that 3rd seat may bid 4♠ (maybe NV on nothing but a long suit) before opener gets a chance to bid 4♥ if he accepts, or 3♥ to not accept. He is in an awkward situation of your own making. Even 3♠ is a problem.

Let's say that without intervention your 4-card invitation of 3♣ is defined as up to 12 and your J2N 4-card support is defined as 13+. (The exact split is not the point.) After 1♥ (p) 3♣ (4♠) he may know the best call is double (penalty). After 1♥ (p) 2NT (4♠) he may ask for aces or make a slam try. If you combine both those bids into a Jordan 2NT, how does he proceed after 4♠? If he doubles and you have the 13 hcp hand and bid on, it is the wrong decision half the time.

My 4 card invitation IS 3♣ (3M-2), and I see no reason to alter that - more useful than a fit jump over a double, I reckon.