[timjand]

Here's another incident I found interesting, I'd be grateful for help understanding the law. EBU match.

1NT - P - 2C* - P
2D* - P - 4NT - P
5C - X - 5NT - P
all pass

2C is stayman, 2D no 4-cd major
After 5C from N, E enquired what 4NT meant. Answer: "I don't know"
Before the first lead, E asked dummy what 5NT meant. Answer: "4NT was intended as quantitative, but after partner obviously took it as Blackwood, 5NT was asking for Kings".

Not pursued as even if there was an infraction, there was no damage, since the contract made +1 and the worst case was that N/S talked themselves out of a slam.

Still, let's say 11 tricks were made. Could you argue that N should bid after 5NT on the grounds that he thinks it is a Blackwood continuation? Or that S should do something different after 5C? 5C is a very unlikely bid after a quantitative raise so is S allowed to realise that the bid has been misunderstood?

Or can N/S bid what they like considering they aren't clear on this detail of their system?

Tim

[pran]

timjand, on 2016-October-09, 02:56, said:

Here's another incident I found interesting, I'd be grateful for help understanding the law. EBU match.

1NT - P - 2C* - P
2D* - P - 4NT - P
5C - X - 5NT - P
all pass

2C is stayman, 2D no 4-cd major
After 5C from N, E enquired what 4NT meant. Answer: "I don't know"
Before the first lead, E asked dummy what 5NT meant. Answer: "4NT was intended as quantitative, but after partner obviously took it as Blackwood, 5NT was asking for Kings".

Not pursued as even if there was an infraction, there was no damage, since the contract made +1 and the worst case was that N/S talked themselves out of a slam.

Still, let's say 11 tricks were made. Could you argue that N should bid after 5NT on the grounds that he thinks it is a Blackwood continuation? Or that S should do something different after 5C? 5C is a very unlikely bid after a quantitative raise so is S allowed to realise that the bid has been misunderstood?

Or can N/S bid what they like considering they aren't clear on this detail of their system?

Tim

I do indeed wonder what the real partnership understanding is (or should be) here.

In my world 1NT - 4NT is a quantitative raise and 1NT - 2C - some response - 4NT is Blackwood.
the 2C bid is simply inserted to change the meaning of the forthcoming 4NT from quantitative to Blackwood.

With this understanding the 5NT bid is asking for kings for the purpose of choosing between 6NT and 7NT as the contract.

If South gets "cold feet" and wants to park in 5NT he should be able to bid 5Sp (unbid suit) requesting a 5NT bid from North. This is not a very advanced agreement, I consider it next to general bridge knowledge.

I find 5C very unlikely even with a Blackwood 4NT correctly understood. Zero aces? All four aces (South must obviously have at least one)? What is the HCP for the 1NT opening bid?

Something certainly seems to have gone off the rails here and I don't know how to rule without first finding out what it is.

[timjand]

pran, on 2016-October-09, 03:53, said:

I find 5C very unlikely even with a Blackwood 4NT correctly understood. Zero aces? All four aces (South must obviously have at least one)? What is the HCP for the 1NT opening bid?

Something certainly seems to have gone off the rails here and I don't know how to rule without first finding out what it is.

12-14 NT and presumably 5c is zero aces.

Tim

[sanst]

Whatever the agreements are, you're not allowed to use the information that the explanation gives. And that's exactly what N does. He thinks that 4NT is asking for aces, hears that it's quantitative and decides that 5NT is not asking for kings but the contract according to S and passes. Blatant use of UI which deserves a serious warning or penalty, notwithstanding that the result for NS is already a bad one.
The restrictions are on N, S can bid as he likes. The 5♣ makes clear that N misinterpreted his 4NT and that is AI to S.

[lamford]

sanst, on 2016-October-09, 04:40, said:

Whatever the agreements are, you're not allowed to use the information that the explanation gives. And that's exactly what N does. He thinks that 4NT is asking for aces, hears that it's quantitative and decides that 5NT is not asking for kings but the contract according to S and passes. Blatant use of UI which deserves a serious warning or penalty, notwithstanding that the result for NS is already a bad one.
The restrictions are on N, S can bid as he likes. The 5♣ makes clear that N misinterpreted his 4NT and that is AI to S.

I don't think you have read the OP correctly. We are told: "Before the first lead, E asked dummy what 5NT meant". Prior to that the only UI transferred was to South, who learned that North did not know what 4NT meant. I agree that conveys little as North responded 5C. If West had asked before he passed what 5NT had meant, that would indeed convey UI to North, and he would be constrained. However, the UI would be that his partner intends 5NT as forcing, despite the lack of aces opposite. That might demonstrably suggest showing how many kings he has, and Pass might be an LA not demonstrably suggested by the UI. That does raise interesting issues as to whether West asking what 5NT means with the intention (or likelihood) of transferring UI to North might be an infraction, especially as he has no intention of bidding and can wait until the auction is over.

So, I think you have given the wrong answer even to the wrong question and North can bid what he likes as he does not have any UI. Unless South folded his cards and wrote down the contract after bidding 5NT, in Chimp style.

[sanst]

lamford, on 2016-October-09, 05:47, said:

I don't think you have read the OP correctly. We are told: "Before the first lead, E asked dummy what 5NT meant". Prior to that the only UI transferred was to South, who learned that North did not know what 4NT meant. I agree that conveys little as North responded 5C. If West had asked before he passed what 5NT had meant, that would indeed convey UI to North, and he would be constrained. However, the UI would be that his partner intends 5NT as forcing, despite the lack of aces opposite. That might demonstrably suggest showing how many kings he has, and Pass might be an LA not demonstrably suggested by the UI. That does raise interesting issues as to whether West asking what 5NT means with the intention (or likelihood) of transferring UI to North might be an infraction, especially as he has no intention of bidding and can wait until the auction is over.

So, I think you have given the wrong answer even to the wrong question and North can bid what he likes as he does not have any UI. Unless South folded his cards and wrote down the contract after bidding 5NT, in Chimp style.

Sorry, I mixed up the timing of the questions. But I don't think the W asked what 5NT means with the intention of transferring UI to N .

[RMB1]

(It would help if the bidding diagram was labelled "NESW" - even better if West was first.)

timjand, on 2016-October-09, 02:56, said:

Still, let's say 11 tricks were made. Could you argue that N should bid after 5NT on the grounds that he thinks it is a Blackwood continuation? Or that S should do something different after 5C? 5C is a very unlikely bid after a quantitative raise so is S allowed to realise that the bid has been misunderstood?

North does not have unauthorised information when he passes after 5NT. We know that North did not know what 4NT was and North was free to guess what 5NT is.

South does have unauthorised information and there are possible alternative calls, depending on how South might interpret 5♣.
Even opposite a quantitative 4NT, 5♣ could be 0 aces, or it could be natural offering 5♣ or 6♣ as alternatives to 5NT/6NT. The "don't know" answer makes some meanings of 5♣ less likely and makes the consequences of some calls by South more dangerous. 5NT is suggested by the unauthorised information as it (appears) to clarify the intended natural meaning of 4NT. It is possible that Pass is a logical alternative (if 5♣ is natural we could play there) or 5♠ (old fashioned blackwood continuation, to sign off in 5NT). We would need to know South's hand and ultimately poll South's peers.

timjand, on 2016-October-09, 02:56, said:

Or can N/S bid what they like considering they aren't clear on this detail of their system?

No. Not knowing your system does not mean you can use unauthorised information.

[StevenG]

I have seen countless quantitative/Blackwood mixups, and a suit response has meant that it was interpreted as Blackwood in every case I've ever seen.

[blackshoe]

---

[pran]

pran, on 2016-October-09, 03:53, said:

I find 5C very unlikely even with a Blackwood 4NT correctly understood. Zero aces? All four aces (South must obviously have at least one)? What is the HCP for the 1NT opening bid?

Something certainly seems to have gone off the rails here and I don't know how to rule without first finding out what it is.

timjand, on 2016-October-09, 04:14, said:

12-14 NT and presumably 5c is zero aces.

Tim

I think that the 5C bid by North clearly reveals (to everybody!) that he understood the 4NT bid as Blackwood. I cannot imagine what the 5C bid should mean as a response to a quantitative 4NT unless they have very advanced partnership understandings.

South will now be aware of North's misunderstanding from the auction (which is AI to South) and not only from the explanation given by North (which is UI to South).

Is South still prevented from varying his auction according to North's misunderstanding and bid 5NT as a question on Kings or bid 5Sp as a transfer to 5NT for play?

North quite possibly has a 12-14 NT without any aces (a maximum hand with K, K, K and KQ will do as will a minimum hand with QJ, QJ, QJ and QJ), and to him the 5 NT bid must mean that South has all 4 aces and wants to know how many Kings North has. An obedient North will respond correspondingly to the 5NT bid. So far no use of UI, only a bunch of MI.

[weejonnie]

Some players (over a quantitative 4NT bid) would use 5C as saying - I am not max but I have a decent club suit. Could 6 Clubs Make? Partner signs off in 5NT or bids 6 Clubs.

[sfi]

pran, on 2016-October-09, 08:07, said:

I think that the 5C bid by North clearly reveals (to everybody!) that he understood the 4NT bid as Blackwood. I cannot imagine what the 5C bid should mean as a response to a quantitative 4NT unless they have very advanced partnership understandings.

In all my partnerships it accepts the slam try and shows a 4 card club suit to suggest 6C. I've always assumed this is totally standard.

[Vampyr]

pran, on 2016-October-09, 03:53, said:

In my world 1NT - 4NT is a quantitative raise and 1NT - 2C - some response - 4NT is Blackwood.
the 2C bid is simply inserted to change the meaning of the forthcoming 4NT from quantitative to Blackwood.

Then you must have some complicated Baron arrangements, or be playing 4-card transfers or something else that will allow you to find 4-4 fits. Such agreements would probably have been mentioned by the OP.

sfi, on 2016-October-09, 14:53, said:

In all my partnerships it accepts the slam try and shows a 4 card club suit to suggest 6C. I've always assumed this is totally standard.

I think that accepting and showing aces along the way is another popular treatment - e.g. you have a probable source of tricks which will be enough for slam as long as they can't cash two aces first.

[barmar]

pran, on 2016-October-09, 03:53, said:

In my world 1NT - 4NT is a quantitative raise and 1NT - 2C - some response - 4NT is Blackwood.
the 2C bid is simply inserted to change the meaning of the forthcoming 4NT from quantitative to Blackwood.

I could believe something like this if opener shows a major -- 4NT would agree on that major and ask for key cards. But after a 2♦ response, it doesn't make as much sense -- what's the key suit? I think most would use Gerber there.

My personal preference, but it's a relatively advanced treatment, is that after a major response to Stayman, 3 of the other major agrees on the suit and shows slam interest. Then you can start cue bidding and use whatever your preferred form of Blackwood is. Therefore, if you jump to 4NT without first going through 3OM, it's quantitative without a fit in the major that opener bid.

[barmar]

StevenG, on 2016-October-09, 07:25, said:

I have seen countless quantitative/Blackwood mixups, and a suit response has meant that it was interpreted as Blackwood in every case I've ever seen.

If he bids a major after having previously denied one in the Stayman response, this is surely what's going on.

But a minor could be a choice of slams. Only if you know that it's a quant/BW mixup would you make the assumption that it's a BW response. And in the OP, when the player says he doesn't know, that tells you that there's confusion, and probably makes it more likely that he treated it as BW.

So now we need to see the hand of the 5NT bidder. The UI suggests that 5♣ was not natural, so if he has club support we probably have to adjust to whatever the result of 6♣ would be (well, not in the actual case, since the NOS was not damaged).

[richlp]

pran, on 2016-October-09, 03:53, said:

I do indeed wonder what the real partnership understanding is (or should be) here.

In my world 1NT - 4NT is a quantitative raise and 1NT - 2C - some response - 4NT is Blackwood.
the 2C bid is simply inserted to change the meaning of the forthcoming 4NT from quantitative to Blackwood.

With this understanding the 5NT bid is asking for kings for the purpose of choosing between 6NT and 7NT as the contract.

If South gets "cold feet" and wants to park in 5NT he should be able to bid 5Sp (unbid suit) requesting a 5NT bid from North. This is not a very advanced agreement, I consider it next to general bridge knowledge.

I find 5C very unlikely even with a Blackwood 4NT correctly understood. Zero aces? All four aces (South must obviously have at least one)? What is the HCP for the 1NT opening bid?

Something certainly seems to have gone off the rails here and I don't know how to rule without first finding out what it is.

To each his own. For me 4NT is still quantitative after the Stayman bid. Had I wanted simply to ask for Aces I would have bid 4C (Gerber)

[Vampyr]

barmar, on 2016-October-10, 13:59, said:

My personal preference, but it's a relatively advanced treatment, is that after a major response to Stayman, 3 of the other major agrees on the suit and shows slam interest.

I think this is totally standard.

[VixTD]

barmar, on 2016-October-10, 14:07, said:

So now we need to see the hand of the 5NT bidder. The UI suggests that 5♣ was not natural, so if he has club support we probably have to adjust to whatever the result of 6♣ would be (well, not in the actual case, since the NOS was not damaged).

If 5NT made and 6♣ would have failed, the NOS were damaged.

[helene_t]

The only UI here is that S has been told that North didn't understand the 4NT bid. It is not clear how that could influence his decision. Apparently he thinks that 5NT asks for kings, so it is a bit strange that he now elects to make that bid instead of bidding 6NT. Maybe he has an ethical obligation to pass 5♣ or to raise to 6♣ on the basis of the theory that if 4NT had been explained as natural, 5♣ would have been natural also. Maybe he thought he had an ethical obligation not to bid 6NT because a natural 5♣ bid (as it might have been without the UI?) would not have guaranteed enough aces for slam.

If any lesson is to be learned from this then it is that EW should not ask such questions. Questions almost always put opps at risk of providing asnwers that result in UI. Here, luckily, it probably didn't matter. But next time it might. Of course you sometimes have to ask questions. But in this case it is hard to see why EW needed to ask about 4NT before the end of the auction.

[barmar]

Vampyr, on 2016-October-10, 17:52, said:

I think this is totally standard.

Maybe on your side of the pond. I've had to teach this convention to quite a few partners. Before teaching them, I often ask them what they think it would mean. Some guess that 1NT-2♣-2♥-3♠ is a splinter. II don't remember what they said about 3♥ over a 2♠ response.