[Wainfleet]

Where does the 33 HCP guideline for 6NT come from? I realise that there are lots of other factors such as shape, teams vs pairs, vulnerable vs not vulnerable, the quality of the field etc. Presumably there has been some computer modelling over millions of hands to support the basic guideline. I think I read somewhere that two flat hands with 33 HCP makes just over 50% of the time on best play.

Many thanks in anticipation.

[smerriman]

Whenever there's a question like this, Richard Pavlicek usually has an answer somewhere on his site

http://www.rpbridge.net/8j25.htm

Quote

One clear message, defying traditional belief, is the HCP requirement for 6 NT. Pedants for years have dictated 33 HCP, but statistics show that only 31, on average, makes 6 NT a winning venture (except for lopsided divisions of 24-7 or worse). Similarly, 35 HCP is the average threshold for 7 NT to be profitable. The obvious implication is to loosen up your quantitative bidding at IMPs, though you need to be more wary of being off two cashable tricks (or an ace in 7 NT).

33 and 37 probably came about as a simple guideline that you're not off two and one aces respectively (with AK of the same suit much less likely).

[thepossum]

Gerber anyone

I just made 7 with 35. It works

It needed a finesse of a Queen of course

Its possible a better player may have known or setup the situation for the Queen to be onside, but not me

Living dangerously can be fun sometimes

[Cyberyeti]

What is profitable also depends on the field, bidding 7 where some people will manage to miss 6 as always seems to happen in weak club fields, requires it to be better than in a field of internationals. Also 33 and 37 are for 2 balanced hands, we've bid 7N on 30 knowing we were claiming at trick 1 (3N-7N AKx, AKx, xxx, AKxx opposite ♦AKQxxxx)

And I agree with smerriman about the derivation

[nullve]

Joke formula I often think about when people say points don't take tricks:

E=mc^2,

where

E = # of tricks
m = # of points
c = 3/5

.

So e.g.

9 = m*(3/5)^2 => m = 25

and

12 = m*(3/5)^2 => m = 100/3 ~ 33

.

[LBengtsson]

Wainfleet, on 2022-October-27, 01:52, said:

I think I read somewhere that two flat hands with 33 HCP makes just over 50% of the time on best play.

That is the key part of the sentence: just over 50% so it is in your favor to bid a small slam most of the time with 33HCP.

[bluenikki]

Wainfleet, on 2022-October-27, 01:52, said:

Where does the 33 HCP guideline for 6NT come from? I realise that there are lots of other factors such as shape, teams vs pairs, vulnerable vs not vulnerable, the quality of the field etc. Presumably there has been some computer modelling over millions of hands to support the basic guideline. I think I read somewhere that two flat hands with 33 HCP makes just over 50% of the time on best play.

Many thanks in anticipation.

It's really 34.

When the 33 is missing the AK of the same suit, you will always be down when both are with the opening leader. You will be down at least 25% of the time when both are with the non-leader. You will sometimes be down when the ace is with the opening leader.

[DavidKok]

smerriman, on 2022-October-27, 02:31, said:

Whenever there's a question like this, Richard Pavlicek usually has an answer somewhere on his site

http://www.rpbridge.net/8j25.htm


33 and 37 probably came about as a simple guideline that you're not off two and one aces respectively (with AK of the same suit much less likely).

Contrary to this (classical) result, I think double dummy favours declarer compared to single dummy in the slam zone, and even more so when both hands are balanced. Any finesses will be taken correctly, all guesses on which suit will break and which will split unfavourably will be guessed right, etc.
I think sticking at least one but really two points over the double dummy recommendation for 50% rate is very sensible, though the IMP gains per board on the 32HCP table are daunting.

[mikestar13]

bluenikki, on 2022-October-27, 05:00, said:

It's really 34.

When the 33 is missing the AK of the same suit, you will always be down when both are with the opening leader. You will be down at least 25% of the time when both are with the non-leader. You will sometimes be down when the ace is with the opening leader.

But with 33 the chances of the missing point being precisely AK suited is rather small, and is then only a sure set if they are in the opening leader's hand. Surely a worthwhile risk.

[johnu]

Another key to bidding 6NT with 2 balanced hands is having 10+ controls, (ace = 2 controls, king = 1 control) in addition to having enough points to produce 12 tricks.

Obviously if you are missing AK (i.e. holding only 9 controls) in the same suit, you may be down at trick 2. Or if the missing AK is in your long suit, you may not have 12 tricks in the other 3 suits. If the AK are in different suits, you probably have to finesse for the king so slam is on a finesse, assuming bad breaks don't decrease the 50% finesse.

Similarly, for 7NT, you want to have all 12 controls, otherwise you will normally have to finesse for a king to have a chance.

George Rosenkranz invented 2 conventions, CONFI for small slams, and Super CONFI for grand slams whose goal was to determine if there was the necessary controls present, and then investigate whether a suit slam was going to be better.

[thepossum]

Has anyone ever extended Gerber to Queens 6C etc

Difference between 1 and 2 out against you could be important

You may even have to finesse a Jack

[gszes]

nullve, on 2022-October-27, 04:29, said:

Joke formula I often think about when people say points don't take tricks:

E=mc^2,

where

E = # of tricks
m = # of points
c = 3/5

.

So e.g.

9 = m*(3/5)^2 => m = 25

and

12 = m*(3/5)^2 => m = 100/3 ~ 33

.

no wonder i have no clue. This game really is rocket science. )

[thepossum]

Out of curiosity I ran a small analysis and made some graphs.
Totally unnecessary of course

But I reckon whatever the stats based on points alone may show, checking controls is useful too

[bluenikki]

thepossum, on 2022-October-27, 15:58, said:

Has anyone ever extended Gerber to Queens 6C etc

Difference between 1 and 2 out against you could be important

You may even have to finesse a Jack

Goren actually suggested it in the late 50s

[jillybean]

Interesting thread , like so many of the "rules" taught when learning this game, it's a good guideline.
The real fun starts when you develop hand evaluation skills and start bidding sub 30 point slams.

[pescetom]

I think that the idea of checking controls with two flat hands of 33 HCP total is dubious at any level and pure misguidance to Novice/Beginners.
Start with looking for shape and fits, if there is neither then quantity of HCP is enough to go on. Later on, learn how to check for controls when a suit slam looks likely.

[hrothgar]

Wainfleet, on 2022-October-27, 01:52, said:

Where does the 33 HCP guideline for 6NT come from? I realise that there are lots of other factors such as shape, teams vs pairs, vulnerable vs not vulnerable, the quality of the field etc. Presumably there has been some computer modelling over millions of hands to support the basic guideline. I think I read somewhere that two flat hands with 33 HCP makes just over 50% of the time on best play.

I suspect that these guidelines significantly pre-date the use of computers to model the trick taking ability of various bridge hands.

If I had to guess, 7 HCPs means that you can't be off two aces...

[johnu]

pescetom, on 2022-October-28, 10:17, said:

I think that the idea of checking controls with two flat hands of 33 HCP total is dubious at any level and pure misguidance to Novice/Beginners.

At the basic level, you frequently won't know whether you have 32 or 33 HCP. Checking for controls when you can (aces in this case) is trivial and not checking when you are missing 2 aces will just make you look silly.

Sure, if you want to remain at the novice/beginner level in evaluating hands then don't bother checking for controls. Looking at old bridge books and world championships from the Goren area, in general, novice/beginners play a much more complicated/artificial system than many of those world champions from the very distant past who played very simple natural systems (and frequently changed partners).

[pescetom]

johnu, on 2022-October-28, 13:39, said:

At the basic level, you frequently won't know whether you have 32 or 33 HCP. Checking for controls when you can (aces in this case) is trivial and not checking when you are missing 2 aces will just make you look silly.

Sure, if you want to remain at the novice/beginner level in evaluating hands then don't bother checking for controls. Looking at old bridge books and world championships from the Goren area, in general, novice/beginners play a much more complicated/artificial system than many of those world champions from the very distant past who played very simple natural systems (and frequently changed partners).

In my experience Novice/intermediate are usually desperate to check for Aces and Kings here, Advanced are not. There are reasons why experts deride use of Gerber with two balanced hands. When was the last time in a similar situation you avoided a slam that others bid quantitatively and lost ?

In any case, Novice beginners deserve advice that is appropriate to their level. Quantitative bidding is effective and simple and under used, to be encouraged IMHO.

[thepossum]

I have no problem encouraging the use of quants if your partner can do basic addition
Sadly some of us have partners that use inadequate DD sims to choose a bid, and ignore basic control checks

I have found Gerber useful on a few occasions but if the auction allows would prefer to use Blackwood

EDIT Can anyone advise why some so deride Gerber as to never find a time to use it?