[Stefan_O]

diagram

See 4NT description.

???

[1eyedjack]

Yes the description of 4N is no narrower than the previous 1S. Meaning that it is undefined by the rules. I expect there is a more long winded way of setting spades as trump and forcing, after which 4N would be rckb for S

[1eyedjack]

There is a case for 4N being quantitative in this sequence. What else to do, for example, with a balanced 18 count, a positional guard in oppo suit, and only 4 spades?

And opposite a quantitative 4N there is a case for North passing. Sadly, however, if North iinterprets no meaning at all for the 4N then I think it would normally pass even with extras.

[iandayre]

And the perfect contract was reached. Agree 4NT should have been RKC for S.

[Stefan_O]

iandayre, on 2016-August-07, 13:39, said:

And the perfect contract was reached. Agree 4NT should have been RKC for S.

Perfect contract, true
Two tables had this auction in Robot Duplicate and got 96,43%.
Pure fluke, of course...

[1eyedjack]

In f2f partnerships we tend to follow a simple algoriyhm:

If
There is a case/demand for quant 4N, and
a trump fit can only be inferred on the bidding to date (ie not yet expressed), and
The trump fit could yet be expressed in a forcing auction below (and to be followed by) 4N
Then
4N = quant.

That algorithm would tend to define 4N as quant here, but I agree that I don't think that Gib abides by these rules

[Stefan_O]

1eyedjack, on 2016-August-07, 14:01, said:

In f2f partnerships we tend to follow a simple algorithm...

What means "f2f"?
And whom exactly are "we" here?

1eyedjack, on 2016-August-07, 14:01, said:

If
There is a case/demand for quant 4N...

That seems like a very dubious criteria/formulation, prone to cause misunderstandings/conflicting interpretations...

[Stefan_O]

Also note that X was support-double.

[lycier]

Stefan_O, on 2016-August-07, 07:48, said:

diagram

See 4NT description.

???

See your diagram.

---

First
Now we can see this " Bug " is caused deliberately by human, not a " Bug " automatically triggered by any Gib .
I would think this issue is caused by unperfect / worse Gib CC, obviously.

Second
How many issues are there in this situation?

---

After support double, Gib CC over 4♠ :
1- 4N= 4+♠,6+TPs.
2- 5♣= 4+♠,biddable ♣, 6+TPs.
3- 5♦= 5+♠, 17+TPs, forcing to 5♠.
4- 5♥= 5+♠, biddable ♥, 4-card ♠, 6+ TPs.
5- 5♠= biddable ♠, 6+TPs.
6- 5N= 4+♠,6+TPs.
7- 6♣= 5+♣,4+♠,20+TPs.
8- 6♦= 5+♠,20+TPs,forcing to 6♠.
9- 6♥= 6+♠,strong rebiddable ♥,4-card ♠,20+TPs.
10- 6♠= 5+♠,20+TPs.
11- 6N= 4+♠,22-24HCP


Here I feel really sorry for this, hoping programming staff would understand me.

[1eyedjack]

In answer to some posts above (on mobile so no quotes sorry).

"f2f" means "face to face". Ie offline bridge.
"We" in this context means "my partner and I".

The "support double" does not promise a fit. Indeed it expressly denies a fit when partner has only 4 x spades for 1S, as the double denies a 4th Spade.

Expert partnerships invariably adopt a mixture of blackwood and quant depending on context. If you are going to mix quantitative 4N with Blackwood then it behoves you to have an agreement of when each applies.

The range of possible contexts in which, absent agreement, a partnership might be called upon to interpret 4N is vast. It may be unreasonable to agree explicitly on the meaning of 4N to cater for all possible preceding auctions. So the algorithm needs to be relatively simple, yet return a sensible result.

A poorly constructed algorithm may lead to an absurd meaning of 4N on occasion, or to occasions where interpretation remains ambiguous. Even then, having that agreement in place will be an improvement over having none.

I don't insist that you or anyone else adopts my algorithm . I simply observe that it has worked for me. Indeed I mentioned above that I do NOT believe that Gib follows it (precisely).

My general observation is that expert pairings use quant 4N in many situations where beginners and intermediates default to blackwood.

So far none of the other responders in this thread (who favour the blackwood interpretation of 4N here) have indicated how they would have bid the hand if holding a hand suitable for quant 4N (or even acknowledged that holding such a hand is possible )