[mikl_plkcc]

Till now, I still have so many misunderstandings with my partner where my 4NT means NT and he interprets it as BW.

In the following auctions, should 4NT be natural or RKCB?

1.
1♥ - 2NT (natural)
4NT

2.
1♠ - 2♦ (invitational or better)
2♥ - 3♣ (4th suit artificial, asking for ♣ stop)
4NT

3.
(2♠) - X - (3♠) - 4♥
(/) - 4NT

4.
(2♠) - / - (3♠) - 4♥
(/) - 4NT

5.
(3♣) - 3♥ - (/) - 4♦
- (/) - 4NT

[Antrax]

For me:
1. Nat
2. Nat
3. BW
4. No agreement.
5. No agreement - should probably be BW.

[EricK]

If in 1, 'natural' means balanced, no ♥ fit and 10-11 points (or something like that), then I don't see how 4NT as natural can help much. I have already shown my hand, so on what am I meant to base my next decision? So I think this ought to be BW, with ♥ agreed.

In 2, this should be natural IMO. No suit is anything like agreed, and opener needs to be able to show extras here, lest the bidding stop in 3NT when responder fears opener is minimum.

In 3, if partner had a strong balanced hand I suspect he would have bid NT at the last turn. We have bid a suit he has suggested that he has, so this looks like BW to me.

For 4, I can't envision a hand which would pass 2♠, and yet is confident that 4NT is a better contract than 4♥. So I don't think this could be natural. I suppose he could be trying to show the minors (in something like a 2056 hand, too weak to bid first time around. But most likely he has a few ♥ (maybe HH or Hxx), enough length in ♠ to envision shortage in our hand, and some strength in the minors i.e. a strongish hand without a convenient bid on the previous round. I would probably take this as Blackwood - but would be hoping that my response also happens to be in my longer minor

And in 5, partner is more likely to have a balanced-ish hand with a good ♥ suit and the ♣ stopped, than a hand with ♦which is confident that slam just depends on the number of keycards I hold. So I would take this as natural.

[Zelandakh]

1. The traditional meaning of any 4NT raise oif a natural NT bid is quantitative. Whether it should be is another matter but that is what it is without discussion.
2. Opener is showing a max 2♥ rebid (~18) and a club stop.
3. This one is RKCB. If you had the big balanced hand then you would either pass or make a slam try.
4. Probably "does not exist" for most pairs, or rather "I want a new partner". The majority of club players would certainly take it as RKCB; "pick a minor" is probably better. I am interested which hand you or your partner had to make the bid (and what the misunderstanding was).
5. The most difficult. Again, I would expect the vast majority of club players to play this as RKCB. With good agreements, natural is possibly better since you can cue 5♣ to make a slam try. Honestly though, at your level it is probably best to have a simple meta-agreement for nebulous situations like this, either "4NT is natural if this makes sense" or "4NT is RKCB unless obviously not", and then work within that and flag up any exceptions you both agree to. Remember that having the same agreement as your partner is more important than having the optimal agreement. And try to avoid making nebulous bids where there is a large window for a misunderstanding.

[P_Marlowe]

#1 RKCB, due to the limited nature of the bid, this is one is certainly unclear
#2 Natural
#3 RKCB
#4 RKCB
#5 RKCB

With kind regards
Marlowe

[fromageGB]

All ace asking except (2).
A simple rule that many seem to play is "4NT is ace asking unless partner has just bid or invited NT with a 3 point range or more, in which case it is is natural."

On this basis, (1) is natural if you play 10-12, ace asking if 11/12, and (2) is natural because partner has shown strength for 3NT but has not limited his hand.

(4) is unusual, perhaps, because can a passed hand be so good as to go slamming? This may be an unusual NT with both minors. Maybe you should add an extension to the simple rule.

[broze]

fromageGB, on 2013-May-15, 11:09, said:

A simple rule that many seem to play is "4NT is ace asking unless partner has just bid or invited NT with a 3 point range or more, in which case it is is natural."

This would mean 2NT (20-21) - 4NT is Ace asking. Simple effective rules are always difficult to create.

[Codo]

I have a rule that 4 NT is NEVEr invitational if partners hand is limited within two points, no matter whether this is 20/21 or 11/12. And for this rule we do not care whether partner maybe upgrade or downgrade a ton of hands.

So 2 NT 4 NT is aceasking for us...

For your examples:
1. If 2 Nt is 10-11 4 NT quant makes no sense, so it is KC for hearts. But is is too hard for me to construct a hand with this bidding. If 2 NT is an old fashioned 13-15, 4 NT is surely quantitative.
2. quantitative.
3. KC
4. I have no idea. Does this really exists? Maybe both minors too weak to bid at once?
5. natural.

[Zelandakh]

2NT - 4NT shows clubs for me. If you want a bid for ace-asking or inviting then 4♠ does the same job only better.

[lowerline]

1. RKCB
2. Natural, 18-19 with club stopper
3. RKCB
4. RKCB
5. RKCB, diamonds trump

[Cyberyeti]

1: Natural, 4♠ would be keycard
2: Natural
3: Keycard, 4♠ is a big heart raise
4: Keycard, 4♠ is a big heart raise
5: Natural

[Siegmund]

Re #1, surprised to see so many people fretting over 10-12 vs 11-12... the traditional meaning was natural and game-forcing.

With one regular partner we explicitly agreed auction #1 would be blackwood, our only exception to "notrump raises are always quantitative."

As already mentioned, #4 might be pick-a-minor rather than blackwood (but it's not to play, thats for sure.)

Without discussion I would assume quantitative for 1/2 and blackwood for 3/5... but I would be very wary of using either of the first two auctions without having discussed it.

[fromageGB]

mikl_plkcc, on 2013-May-13, 22:35, said:

1.
1♥ - 2NT (natural)
4NT

Siegmund, on 2013-May-22, 08:52, said:

Re #1, surprised to see so many people fretting over 10-12 vs 11-12... the traditional meaning was natural and game-forcing.

4NT is still game forcing whichever way you play it