[mikl_plkcc]

Last night, we had an auction which ended up

(1NT) - 2♦! (6-card suit) - (6♦)

Advancer didn't know how to continue and passed, we missed a good fit and they made their off-field slam.

What's the follow up if the responder continues to bid after 2♦?

[DavidKok]

I'd use the same structure as when the opponents interfere over your 2♦ multi opening. For me that depends on whether the interference was double, 2M, 2NT-3♦, or higher.
This is a common theme - if you are going to use any competitive bid, particularly a competitive artificial bid, most of your time and effort should be on the continuations in competition. More often than not your opponents will be in the auction, so that's where your agreements should be most fleshed out.
I'm not sure this is a natural bidding question.

[mikl_plkcc]

We don't play multi 2♦ opening.

[DavidKok]

Sorry, I'll rephrase:

You are using a competitive tool after the opponents have made a pretty strong opening. You should expect further competition. Agreeing on continuations after responder bids over your 2♦ overcall is one of the most important parts of the bid. The structure I recommend is the same as I recommend if the opponents overcall after a multi 2♦ opening. If you don't have experience with such an opening you're at a disadvantage, but I still recommend the same structure (though I think my personal structure is too complicated and detailed to recommend). Alternatively, you can consider this a system loss and go for something easier or continue without detailed agreements.

[P_Marlowe]

Hi,

#1 if your side showed a long suit, a good idea is to agree, that this is the suit you play.
#2 2D usually does not show an arbitary single suiter, it usually showes a major suit 1-suiter.

From this followes if you bid a major, it is pass or correct, i.e. 6H would be pass or correct.

Given the seq. you encountered: You have to ask yourself, how confident are they to make.
You did not state the strength of the 1NT opening, if it is a weak NT, i.e. 12-14, the 2D should
promise / show at least constr. values. If this is the case, there is a chance, that 6D goes down,
i.e. a sac. is not a good bet.

With kind regards
Marlowe

[mikl_plkcc]

We are using multi landy as the 1NT defence regardless of their 1NT strength, and 2♦ shows an unspecified 6-card suit (can be major or minor - otherwise there is no way to compete with a long minor). We didn't have any agreement about the strength, we just used common sense that it should show values for competing at a 2-major or 3-minor against a 1NT.

I have revisited the board again (board 14). I held 6 ♠ headed by AQ and 4 small ♥, and a K in ♣ doubleton, would it be better for me to bid 2♣ (5-4 in the majors) over 1NT instead? In such case, partner would likely have bid 6♥ in this case, as partner held 5 ♥ and 4 ♠.

We got -8.17 IMPs by letting their 6♦ made, another table sacrificed 6♥, and ended up down 4 doubled, green vs green, and if we could find out 6♠ it would only get down 3 doubled, which would get a positive score.

[DavidKok]

• With 6-4 in the majors I prefer showing both majors to bidding only one of them. Telling partner that we should not be worried about the other (potentially short) major is helpful, and we will find our best fit most of the time.
  
• I dislike your modification of putting all single-suiters in 2♦. Personally I would revert that change as soon as you can. Artificial defences to a 1NT opening by the opponents have to make compromises on which one-suiters and two-suiters they can show, and most sacrifice the ability to show minor-oriented hands to some degree. The reason is quite simple: minor suits don't win partscore competitions, and after their strong NT it's often a partscore competition. If you want to retain the ability to compete in a minor suit, why not use 3♣ and 3♦ directly? Your 2♦ would commit the partnership to that level anyway.
  
• You would do well to agree on a strength range over the opponents' NT opening. It is common to permit weak interference over their strong NT, but demand more strength if the 1NT opening was weak or kamikaze. 'Just use common sense' does not cut it, in my opinion.
  
• To me it is a pretty far leap to infer that, had you bid 2♣ showing the majors, partner would bid 6-over-6 on this auction. The opponents bid a making slam, which means you are practically guaranteed a poor score. A not-quite-a-joke that I like is that there's no such thing as a slam that is so good that the whole field can find it. People are just terrible at slam bidding, so if at your table the opponents bid to 6 and it makes (even on a wild guessing auction like this one), it's a bad result.

[mikl_plkcc]

We use all 3 bids over 1NT as preemptive, as they are jump bids.

And, for slam bidding, last week there was a board so good that I bid 7NT, that 6 out of 8 tables bid a grand, and the only table stopped at 4 lost 16.43 IMPs. (It was a board with 34 HCP combined in a partnership, one holding solid ♥ and the other holding solid ♠, so all of 7-majors and 7NT were lay down 13 tricks). And there was another board where the opponents bid a making off-field slam on a 6-1 fit where I misread the auction and made a bad sac!

In an earlier week, there was also a board where everyone bid slam. We bid 6 but lost because it was a 50% grand making (depending on a position of an opponent's card), and 2 tables bid 7!

Are we doomed every time when our opponents bid a making slam?

[DavidKok]

mikl_plkcc, on 2025-March-08, 11:37, said:

Are we doomed every time when our opponents bid a making slam?

Yes.

[mw64ahw]

My Weak only/Multi-2♦ defence wont work here so I'll leverage off Transfer Lebensohl

A useful discussion on BW below
Defending Against 2!d Overcall of 1NT showing one long major suit

A further thought could be to use 2M as a takeout of M while using Lebensohl for the competitive raises etc.

w.r.t to 1N-2♦-6♦. I would find this bid fairly easy to judge and expect a good chance of making. However, knowing whether to interfere is hard given, a) 2♦ doesn't identify the suit, b) the playing strength can be wide ranging bar a minimum expectation so hard to know the sacrifice cost.
Partner can bid 6♥ as Pass/Correct with support, but the outcome may be random.

I like the 2♣ Multi-Landy bid, which would be my choice with 6-4.
In respect of long suits I prefer taking an extended approach to show Strong, Intermediate, Normal and pre-emptive raises. For example

2N-3♣-3♥ Pre-emptive
2♦ Hearts Normal/Strong
3♥ Intermediate

Now 3♣ becomes both minors which differs from Multi-Landy

[P_Marlowe]

mikl_plkcc, on 2025-March-08, 11:37, said:

We use all 3 bids over 1NT as preemptive, as they are jump bids.
<snip>

This is not the best / most sensible, if you play against a weak NT.
Playing against a weak NT, you need the ability to bid your games in
a constructive / controlled manner.

Playing Multi Landy, the X gives you an upper floor for your bids,
but you should also agree on a lower floor.