Bridge & Graphs – Make confident calls when you bid

Bridge Class is out Time to find your way: What will you call with a 16HCP 5332 shape? Will you Bid, Pass or Double?

How good is your judgement?

If like me. you trust yourself more than the unsubstantiated “should dos” of others, then you might be in the right place right now. If you would like to read some statistics to increase your knowledge and hone your own judgement of what to do when faced with a hand that looks like this:

And the opponents open in front of you.

Our team of bridge supervisors this week could not agree on the right bid to make. Should one overcall with only a five card balanced hand with a view to making or gaining from the opponents bidding over us and failing? Bid NT with fingers crossed for good things to happen, or Pass and hope to gain when the opponents contract fails?

5 good bridge principles are in one’s mind at this time. And each wars with itself for supremacy.

1. Balanced hands are for playing in NT, BUT good stoppers are required unless you can run a suit when on play.
2. Because we know the whereabouts of eight cards from the spade suit, a natural conclusion is that partner musn’t have many. moreover we should have a fit if they do. So either we have a fit and they do, or we both don’t.
3. 16-17 HCP is nearly half the pack! We don’t need partner to have many. But if partner only has four points, then the distribution of points is 20-21 each for NS/EW and probably no-one is making anything.
4. How are the points distributed? If both hands partner and the opponents have passed, we only know for sure that we have not missed slam. If West and North each have half the outstanding high card points, then our side has at most a combined 23 count.
5. Vulnerability matters. The Law of Total Trumps says you cannot compete to the 3 level safely with an 8 card fit, especially when vulnerable. And that when the fit is known!

SO: The good principles war suggest PASS could be the answer because points distribution suggest game is not likely, a fit is not guaranteed, and balanced hands without good stoppers are for defending.

BUT say the bidders – “You have to bid in case game is on”

AND still the bidders say – “Anyway it is ludicrous to Pass they say, you have 16 points.”

Are they correct? – Or should I have the courage of my conviction?

I’ve just finished reading Lessons in Chemistry So I thought, I’m going to put a bit of science into my bridge. And I decided to conduct a highly scientific research(not!) experiment to prove my principles or their rhetoric.

These are my findings based on the statistics below.

Bidding 2NT is not much use because 69% of the time we will have a combined 24 count at most & our source of tricks is limited by the likelihood that partner will be balanced or semi-balanced(80%), and there is only a tiny likelihood of making 2NT exactly(2%) which is the most likely spot because partner is more likely to have 6-7HCP and will pass.

3H and PASS however are more interesting and a closer decision. It is unlucky to NOT find partner with a heart fit (24%), but of these 60% will be balanced or semi-balanced.

The makeable contracts graph suggests that if we eliminate 2NT, Pass seems the right bid whenever partner has spade cards, does not have the HCP to raise to game, or does not have a heart fit.

Double has no merit because of the tiny likelihood North has a sufficiently good minor single or two-suiter (20% unbalanced or 5/5 shape)

Pass – the results below show that more often than you might think North will have 3 or 4 spades. It is equally likely that we can make game, as the opponents will go down, and that we can make a game in hearts.

But please make your own study. I very much hope in these graphs below you find more information from which to make your own bid or pass decision on deals that don’t fit the learning mold.

HYPOTHESES:

1. It is ludicrous to pass because you have 16 points
2. North-South might miss game, and
3. North-South should make a part score.

TEST SCOPE: Partner’s hand (North) number of high card points, shape, number of hearts, number of spades

METHODOLOGY: 320 deals were randomly generated giving South 16 HCP and a 2533 shape, and East 6-9 & 6 spades (modern bridge seems to open 1S with 10HCP). These deals were then exported, double dummy analysed and sorted according to the following criteria:

The shapes of North hand was sorted into balanced, semi-balanced, unbalanced and 5/5 – 96 different shapes were found.

The distribution of the shape based on length in hearts and length in spades were sorted.

The high card points were counted and various stats eg frequency, median, average were calculated.

The makeable contracts were identified, filtered and sorted. Par for each board was determined as the simplest way to generate a meaningful rule of thumb guide. 15 different contract levels were filtered into a working list of Grand, Slam, NT Heart or Spade Game, hearts or spade partscore and failing scores for NS and EW. Anything that was below the 2S level was eliminated.

CONSTRAINTS

This analysis does not determine based on passed hand actions by partner or opponents. As such, a lowering re-adjustment should be made when assessing expected high card points and shape if partner or an opponent has already limited their hand shape and points by a Pass.

THE FINDINGS: