Meaning of 3NT after major agreed

[DWM]

I have been getting into situations where we have agreed a major below 3NT and started to cue bid. What do people use the 3NT bid for in these situations?

[kenrexford]

I have heard of at least four different uses for a 3NT call after a major is agreed.

 

First, it could be an offer to play 3NT, notwithstanding the major fit.

 

Second, years ago at least, a "cuebid" of 3NT was an artificial means of cuebidding trumps. In other words, after, say, 1♠-P-3♠, 3NT would show the Ace of Trumps.

 

More modern bidding uses 3NT, in a cuebidding sequence, as either (a.) "Serious" or (b.) "Non-Serious," a general cuebid showing no specific control but indicating the general nature of the "attitude" of the bidder toward a possible slam. There is a lot to these two meanings, and when to be "serious" or "not serious" is a matter that requires a bit of study and a lot of partnership understanding and agreements.

 

I have even seen 3NT used as a pattern completion bid. For example, suppose 1♠-P-2♥-P-3♥-P-3♠-P-3NT. This auction might be one where Opener is "cuebidding" pattern. This would show slam interest with balanced pattern outside, whereas a call of four in a minor would imply a stiff or void in the fourth suit.

[helene_t]

Since this is the beginner/intermediate forum, I recommend you play it as a suggestion to play 3NT. This is because it will sometimes have this meaning anyway and it can couse confuision if it may have a different meaning. (For the same reason, I suggest that 4NT and 5NT are always to play when a minor suit is trump).

 

Most established expert partnerships play "serious 3NT": whenever both partners are more or less unlimited in terms of slamishness, 3NT shows serious slam interest while bypassing 3NT shows no extra slamishness; such a cue-bid is made just in case partner has extras.

 

There are many variants of this convention. Some play "non-serious 3NT": bypassing 3NT shows serious slam interest. I think that is theoretically better since it preserves bidding space for when cue-bidding is more likely to be relevant. Another improvement, suggested by Jeff Ruben, is to play "serious 3♠" when hearts is trump: 3NT shows a spade control if you play it that way.

 

Another use of 3NT is denying a first-round control. Bypassing 3NT shows specifically first-round control, then.

 

In any case, it is not always clear in what situations the convention apply and in what situations 3NT would be to play. So you need to invest some time in discussions with partner if you want to play one of those conventions.

[barmar]

Another case that comes up frequently is when you're unsure that your major suit agreement is really an 8-card fit. There are many cases in an auction like 1min-1Maj-2Maj where opener raises responder's suit with only 3-card support. If responder has only a 4-card suit and a balanced hand, he can invite or force to game with 2NT or 3NT. If opener has 4-card support he will usually take preference back to the agreed major, but with 3-card support he can stay with NT.

[Guest Jlall]

I also recommend playing it as either an offer to play, or if that just isn't logically possible, a natural descriptive bid. For instance when partner splinters 3N to show wastage may be the only bid to slow him down.

[cnszsun]

If both partners are unlimited when major suit agreed at 3 level, mostly after 2/1 seqence, i believe 3nt is best to be played as serious or non-serious 3nt because it's very useful to the slam investigation.

If partner made a limit raise at 3 level, like 1♠-3♠ or bergen-style raise, i see some people play 3nt by opener as short suit asking. I believe this is logical because most of us have no way to show splinter at 3 level. And after 9 cards major fit is found, we rarely want to play in 3nt.

For other cases, as an offer to play seems reasonable.

[DWM]

I can certainly see Helene's point about keeping it as to play. When we have tried other things as non natural meanings we have messed up at times. However, I look at this as part of the learning curve. To try and save mistakes I think we will try non-serious as if one of us forgets they are more likely to continue cue bidding with the big hand.