What is a natural system of bidding?

This is a system which entirely results from SALON and doesn’t incorporate (more frankly, with a few exceptions) anything besides SALON; no artificial bids, no conventions, and no gadgets.

The system is labeled NABOB, which denotes:

 

NATURAL
BIDDING

OBSERVANT

 

The Polish acronym is SOSNA [ pine–tree ]:

SYSTEM   [ system ]

ODZYWEK  [ of bids ]

STYLU   [ style ]

NATURALNEGO [ natural ]

         

 

One–Level–Suit  Opening Bids

    HT = Honor Tricks

Four 1S opening bids (S stands for Suit), denote ALL hands approximately from 4 to 6 HT strong.

The exact minimum strength for 1S is  3 1/2 Honor Tricks, whereas the maximum strength raises up to 6 1/2 HT for the most balanced hands.

NABOB hasn't any natural 1NT opening bid – 1NT is an artificial bid, denoting all hands too strong to open 1S.

2S opening bids (S stands for Suit) are natural and preemptive (with 5  winning tricks).

Minimum Honor Strength

Is the 31/2 HT a properly defined minimum of 1S opening ?

From the viewpoint of Revealing Extras Directive (RED) – yes, because an average hand has 3HT, and the 1/2 HT surplus seems to be a sufficient Positive Deviation (PoD).

From the viewpoint of Strength Assurance Directive ( SAD ) – also yes.

Just see: having 31/2 HT yourself, you will find your partner with almost 2 HT on an average, to which 1 Long Trick (LT) should be added, giving a total of 61/2 Offensive Tricks (OT). Thus, the requirement for a one–level contract is satisfied.

Thus, SAD is satisfied in the more demanding version „What has been bid – is a contract to make”; not only in the version „What has been bid – is a profitable contract” .

Minimum Distribution

In accordance with RED–1 ( Inform about the greatest PoD ), the 1S opening bid should mean that the greatest Positive Deviation pertains to the suit opened.

We assume the following distributional minima for opening bids:

1 minor

=

at least 3 cards in the bidden suit

(with 33 in the minors open the better)

1 Major

=

at least 5 cards in the bidden suit

(a very good 4–card suit will do exceptionally

The average length of a suit opened was found to be:

 

1 minor = 4.38 = 4 1/2

80% of 1 Minor opening bids are based upon at least a 4–card suit,

thus only every fifth 1 Minor corresponds to an exactly 3–card suit

 

1 Major = 5.32 = 5 1/4

Since the average number of cards dealt to a player in a particular suit is exactly 3+ ( 3.25 ), hence the respective values of distributional PoDs (Positive Deviations) for different 1S openings:

1 Minor = +1 1/4  ( but a NeD may also happen! )

1 Major = +2        ( and at least 1.75 in each case ).

The Positive Deviations are significant enough to satisfy the requirement stemming from RED. The low value of PoD accompanying 1 Minor opening and an occurrence of NeD (Negative Deviation) seem to be the only faults.

RED–7 ( „The higher bid – the greater PoD” ) is also satisfied since PoD for 1 Major opening is greater than that for 1 Minor.

Finally, PAD–1 ( „The lower bid – the greater strength or dispersion” ) is satisfied as 1 Minor openings have clearly greater dispersion than 1 Major openings.

The 3–5 Model is the Best

Model „Minor – 3, Major – 5” is no novelty to anybody, but this one has been sufficiently justified, possibly here for the first time.

Culbertson's model „1S with a 4–card suit” is clearly contradictory to both RED–7 and PAD–1, which worsens SAD for 1 Major ).  ???

Clearly, model „Minor – 4, Major – 5” would be the best. However, it is impossible ! 

The Model Hand

Taking under consideration that an average hand contains 3 HT, it comes as no surprise that the average strength of 1 Major opening bid amounts to 4 HT, that is, only a half HT above the indespensible minimum.

The average shape of opener's hand for 1 Suit opening bid is respectively:

1 Minor = (  4 1/2   2 3/4   2 3/4    2 3/4  )

The largest value corresponds to the suit of opening bid.

Some rounding has been allowed for the sake of simplicity.

1 Major = (  5 1/4   2 1/2    2 1/2   2 1/2  )

In the case of 1 Minor opening bid, the differences between the reported values and the exact ones are greater than the respective differences for 1 Major opening bids. The value of dispersion for 1 Minor opening bid is larger than that for 1 Major opening bid. Thus, the maximum relative error due to the rounding is smaller than it would have been otherwise.

For simplicity, and considering that the dispersion of 1 Minor is much bigger than that of 1 Major, we assume, however, the following average distributions:

1 Minor = (  4   3        3       3   )

1 Major = (  5   21/2  21/2  21/2  )

 

 

 

Example

from Pikier 10, 1982

Fragmen­tary vision has to be avoided eve­ry­where !

This rule applies to the game of bridge, espe­cially to the bid­ding, in­cluding solving both the practical problems at the table and the more gen­eral ones in the theo­retician’s labora­tory.

Fragmen­tary vision may lead a theoreti­cian to strange and un­neces­sary con­ven­tions. These may have ap­pearances of having been deeply analyzed and scien­tifically for­mu­lated. The Blackwood Con­vention is an ex­ample. However, a system adopting sev­eral such con­ventions becomes an in­co­her­ent conglom­erate, though each se­quence by it­self seems to be practi­cal. The only right way to bid is through uni­fied, synthetic and total vi­sion.

A proper solution to the bidding should take un­der con­sidera­tion all three NSB Di­rectives even if the require­ments of the par­ticular di­rec­tive aren’t fully met. The optimiza­tion proc­ess must not focus on one criterion only. The combined effect of all criteria should be con­sid­ered.

Thus, in a particular bidding situation one needs to select a bid which agrees most to all three NSB Direc­tives. If a more codi­fied problem arises, then the solution should con­form to the corre­sponding part of SALON.

 

The weight (or relative importance) of each Di­rective remains un­known, un­fortu­nately. Our choice may vary be­tween the best bid and the least evil.

I cannot measure the values of PoDs (Posi­tive Deviations). Neither can I measure the value of disper­sion. The precise al­gorithm hasn’t been worked out yet. Even worse; the very axi­oms are still in cra­dle. 

At this stage, a very gen­eral rule seems ap­propriate. It is supe­rior to Natural Bidding Style Di­rectives.

 

 

Preparation  Meta–Direc­tive

 

 

Not to violate any Directive in future, one has to envis­age a possi­ble de­vel­opment of bid­ding; mi­nor devia­tion are allowed if they pre­vent future aberrations.

 

I would like to repeat: 

Natural Style of Bid­ding, enriched by SALON, constitutes it­self a very good way of bid­ding.

This, how­ever, re­quires con­sid­er­able skill at pre­sent, but I hope that as NASA

and SALON are de­vel­oped the whole task will be­come eas­ier and eas­ier.

The exact proof that NSB plus SALON con­stitute the most precise way of bid­ding is still lacking. At present, I have only some cir­cumstan­tial evidence which I in­tend to pub­lish soon. The exact proof would be the great­est achieve­ment in the history of bridge, I think.

For the moment:

Try to prove that ANY con­vention leads to better final contracts than care­ful natural bid­ding does !


Now, let’s analyze the examples.

Natural Bidding Style is repre­sented by NAtural Bidding OB­servant.

 

 

J x x x

K J x

K Q J x

A x

1¨

 

?

A K x

A Q 10 x x

A x x x

x

 

East has three Posi­tive Devia­tions (PoDs):

a large one – in Hearts    

a con­sider­able one – in Dia­monds     

a somewhat smaller – in Spades

( please notice that had West opened 1§ East’s PoD in Dia­monds would have been equal to that in Spades )  

Therefore, East has to inform about his PoDs in the follow­ing order: © ¨

 

1© re­sponse would make it im­possible to preserve the above or­der as the subse­quent dia­mond bid isn’t forc­ing (mind: “an old suit isn’t forc­ing” rule).

Thus, East should bid 2© which is a game forcing bid. Both his total strength and his PoD in Hearts jus­tify such a bid. A game forcing bid enables East to show PoD in Dia­monds on the next round.

As we see, Prepara­tion Meta–Directive ( PMD ) has been fully applica­ble.

 

 

J x x x

K J x

K Q J x

A x

1¨

 

2©

?

 

 

A K x

A Q 10 x x

A x x x

x

 

West’s opening bid was based upon 4+ HT of which 1+ con­stitutes a surplus value.

It has to be re­mem­bered that a single–jump re­sponse in a new suit as­sumes only 3 HT.

The num­ber cor­re­sponds to prac­tical value of the ex­cep­tion­ally ugly mini­mum opening bid.

 

That 1+ surplus doesn’t have to be immedi­ately an­nounced, yet West should be aware of it.

In reevalu­ating PoDs ( Positive Deviations ) East’s last bid should be consid­ered.

Certainly, East doesn’t expect West to have such a good fit in Hearts. Thus, West’s PoDs at this stage look as follows:

a con­sid­er­able PoD in Hearts

three minor PoDs in the re­maining suits.

 

PoD in each of the re­maining suit  is of, more or less, the same value, ie:

in Spades – there are four spades

in Dia­monds – a very strong 4–card Dia­monds

in Clubs – since the Ace seems to be more valu­able as­set after game forc­ing re­sponse.

Therefore, two rebids may be considered. Either has some dis­ad­van­tages:

2NT – con­ceals large PoD in Hearts

3© – con­ceals smaller PoDs in the re­maining suits.

This con­tradiction may be solved by applying Prepara­tion Meta–Di­rec­tive ( PMD ); it is possible, for in­stance, to bid 2NT first and to show PoD in Hearts later, and it seems to be the better de­cision than to bid hearts first.  [ Written in 1982. Now, I think a heart bid is better. ]

 

 

J x x x

K J x

K Q J x

A x

1¨

 

2©

2NT

 

?

A K x

A Q 10 x x

A x x x

x

 

Certainly, 3¨  (refer to the dis­cussion pertain­ing to 2© bid).

 

 

J x x x

K J x

K Q J x

A x

1¨

 

2©

2NT

 

3¨

?

 

 

A K x

A Q 10 x x

A x x x

x

 

Hearts should be bid, but at what level ?

Now, West has a very large PoD in Hearts (because heart PoD had been concealed by 2NT).

Some ex­tra strength, having been al­ready as­sessed as 1+ HT, wasn’t re­vealed yet, ei­ther.

4© bid meets all require­ments stipulated by both:

RED–7 = The higher the bid – the greater the PoD

SAD–1 = Suit bid means PoD in THIS suit

 

 

J x x x

K J x

K Q J x

A x

1¨

 

2©

2NT

 

3¨

4©

 

?

A K x

A Q 10 x x

A x x x

x

 

Certainly, 4  ( „New suit after raise is forc­ing, even it is a game” )

 

 

J x x x

K J x

K Q J x

A x

1¨

 

2©

2NT

 

3¨

4©

 

4

?

 

 

A K x

A Q 10 x x

A x x x

x

 

The value of the spade suit increased. In the light of his bid­ding so far, West has a Nega­tive Devia­tion (NeD) in Clubs.

So West should bid 5§ as indi­cated by RED–5 = Fourth Suit means NeD in THAT suit.

Such a bid stresses his strength as stipu­lated by PAD–1 ( The Lower the bid – the greater the strength or disper­sion ) and PAD–2a ( New suit is a positive suggestion (strength) ).

4NT would convey Positive Deviation in Clubs. Moreover, ac­cording to SALON pre­sented so far, the 4NT bid would not have been forcing.

 

 

J x x x

K J x

K Q J x

A x

1¨

 

2©

2NT

 

3¨

4©

 

4

5§

 

?

A K x

A Q 10 x x

A x x x

x

 

 

 

 

 

Having qualitatively in­formed about his PoDs (©¨ª ), East has to specify more pre­cisely his values. It seems that only PoD in Hearts has been suffi­ciently em­phasized. 5ª will show not only some PoD in Spades but also PoD in Diamonds, the suit which have been bid be­fore (see RED–1a = In­form about the great­est PoD ). That’s true that Spades are „an old suit”  but not as old as Hearts. Thus, 5ª should be considered a forcing bid.

The bid­ding has indi­cated precisely a sin­gleton in Clubs. Thus, 6§, express­ing a Negative Deviation in Clubs, would have indi­cated a void.

 

 

J x x x

K J x

K Q J x

A x

1¨

 

2©

2NT

 

3¨

4©

 

4

5§

 

5

?

 

 

A K x

A Q 10 x x

A x x x

x

 

 

 

 

 

The value of Dia­monds in­creased considera­bly after East had indi­rectly shown large PoD in this suit.

The value of club Ace, and even Spades, also in­creased.

West hasn’t shown his PoD in Diamonds yet. Neither did he de­scribe his total strength.

7¨ seems to be the only proper bid.

 

As you see, Natu­ral Bidding Style is hardly legi­ble. So it is for me ! 

Neverthe­less, after the bidding has been con­cluded West is able to visualize his part­ner’s hand to every essential card. East may err a lit­tle more.

 

 

 

 

SALON again

 

Pikier Writings

 

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