1m opening length probabilities

[MickyB]

Playing 15-17 NT, Better Minor, 1C on 3-3, 1D on 4-4:

 

What is the probability that partner has 3 cards/4 cards/5+ cards when he opens 1C? And likewise when he opens 1D?

 

Thanks.

[glen]

Playing 15-17 NT, Better Minor, 1C on 3-3, 1D on 4-4

Q. If you are playing 1C on 3-3, 1D on 4-4, can you still play better minor?

[PeterAlan]

Playing 15-17 NT, Better Minor, 1C on 3-3, 1D on 4-4:

 

What is the probability that partner has 3 cards/4 cards/5+ cards when he opens 1C? And likewise when he opens 1D?

 

Thanks.

Depends on what shape / HCP ranges 1m is opened. Or are you implicitly just considering balanced hands? Semi-balanced as well? Specify more fully, and I'll give you some numbers tomorrow.

[MickyB]

Depends on what shape / HCP ranges 1m is opened. Or are you implicitly just considering balanced hands? Semi-balanced as well? Specify more fully, and I'll give you some numbers tomorrow.

 

Ok let's say 11-21 unbal/12-14 bal/18-19 bal. Assume 5m422 in range opens 1NT. Thanks

[MickyB]

Q. If you are playing 1C on 3-3, 1D on 4-4, can you still play better minor?

 

It's a name for a method. It's what most people mean when they use the name. So, yes?

 

When I started playing duplicate, whenever we were asked if we played Better Minor, we would respond that we played Longer Minor. After the first dozen people all explained that that was what they had meant by "Better Minor", we gave in. Sometime afterwards I realised they had just been asking if we played 2+card club or 3+card minors.

[awm]

It's a name for a method. It's what most people mean when they use the name. So, yes?

 

When I started playing duplicate, whenever we were asked if we played Better Minor, we would respond that we played Longer Minor. After the first dozen people all explained that that was what they had meant by "Better Minor", we gave in. Sometime afterwards I realised they had just been asking if we played 2+card club or 3+card minors.

 

The way I've seen it used (and the way my partners and I use it), better minor means that with equal length we tend to open the stronger suit. For example:

 

♠KQxx ♥Kxx ♦AJx ♣xxx would open 1♦, but ♠KQxx ♥Kxx ♦xxx ♣AJx would open 1♣

 

♠Kxx ♥Ax ♦AQxx ♣xxxx would open 1♦, but ♠Kxx ♥Ax ♦xxxx ♣AQxx would open 1♣

[karlson]

The way I've seen it used (and the way my partners and I use it), better minor means that with equal length we tend to open the stronger suit. For example:

 

♠KQxx ♥Kxx ♦AJx ♣xxx would open 1♦, but ♠KQxx ♥Kxx ♦xxx ♣AJx would open 1♣

 

♠Kxx ♥Ax ♦AQxx ♣xxxx would open 1♦, but ♠Kxx ♥Ax ♦xxxx ♣AQxx would open 1♣

 

That seems to be the meaning in the US, but everywhere I've been in Europe, people use it to just mean "longer minor, 1c with 3-3, 1d with 4-4" as MickyB said. The alternatives being various forms of 2+ 1c or 1d.

[aguahombre]

"Better minor" is another in the long line of terms we would not use to describe methods. I would have assumed if someone said better minor, AWM's interpretation was what they meant, but I shouldn't have to figure out what each region of the world calls things...especially when the words don't describe the agreements, as seemingly in this case in the EBU.

 

Balanced 3-3m or 4-4m open 1C in our style; balanced 4-4M open the only 3-card minor. Since that's what we do, that's what we say.

[Free]

That seems to be the meaning in the US, but everywhere I've been in Europe, people use it to just mean "longer minor, 1c with 3-3, 1d with 4-4" as MickyB said. The alternatives being various forms of 2+ 1c or 1d.

You should visit Belgium. :)

 

With one partner I play 3 card minors where 1♦ could contain longer ♣. When we explain sometimes we get the question "so you play longest minor?"... :rolleyes:

[PeterAlan]

Ok let's say 11-21 unbal/12-14 bal/18-19 bal. Assume 5m422 in range opens 1NT. Thanks

Basis:

 

1. Concerned only with 4-3-3-3 to 6-6-1-0 shapes; all 7+ suit hands excluded
   
2. Similarly all 22+ HCP hands, and 11 or 20/21 HCP balanced (4-3-3-3; 4-4-3-2; 5-3-3-2) hands, excluded (not opening 1x)
   
3. All 11-21 unbalanced opened (including 11 HCP 4-4-4-1)
   
4. 5-5 or 6-6 M-m open M; 6-5 m-M open m
   
5. 50% (ie 5m) of 15-17 HCP 5-4-2-2 open 1NT; no 6-3-2-2 do
   

If I've interpreted you correctly, of the hands with no 5+ card suit that are opening 1m:

 

1. 25% of 4-3-3-3 hands open 1♦ (4 card), 25% 1♣ (4 cards) and 50% 1♣ (3 cards)
   
2. 50% of 4-4-3-2 hands open 1♦ (4 card), 8.33% 1♦ (3 card), 33.33% 1♣ (4 card) and 8.33% 1♣ (3 card)
   
3. 75% of 4-4-4-1 hands open 1♦ (4 card) and 25% 1♣ (4 card)
   

(All 5+ card hands that open 1m have the same frequency of 1♦ and 1♣.)

 

Then (E&OE):

 

1. There are 234,166,911,312 1x opening hands in this sample space
   
2. 34,297,838,856 (14.65%) open 1NT and 77,785,551,954 (33.22%) 1M
   
3. 61,884,385,734 (26.43%) open 1♦, of which 2,637,795,564 (4.26%) are 3-card, 25,871,765,277 (41.81%) 4-card and 33,374,824,893 (53.93%) 5+ card suits
   
4. 60,199,134,768 (25.71%) open 1♣, of which 10,353,046,632 (17.20%) are 3-card, 16,471,263,243 (27.36%) 4-card and (again) 33,374,824,893 (55.44%) 5+ card suits
   

I can give you a fuller breakdown if needed: you should probably check what I've done, as I'm perfectly capable of slipping in a silly mistake!

[jogs]

Who knows the relative probabilities? If pard opens 1♣ and RHO preempts 2 of a major, I just bid as if pard started with 5+ clubs.

[Zelandakh]

You should visit Belgium. :)

He should try Germany too. If a pair here describes their system as "Standard American" it means they open 1♣ with 4432 and a 1♦ opening promises 4.

[aguahombre]

Who knows the relative probabilities? If pard opens 1♣ and RHO preempts 2 of a major, I just bid as if pard started with 5+ clubs.

Surely, you meant 3+, not 5+. Or do you have the pleasure of winning part-score battles in a 3-3 fit?

[helene_t]

Here in Yorkshire, "SAYC" means Acol with strong NT and 5cM, 1♣=2+. But that is just as it is on BBO, I suppose.

[cherdano]

That seems to be the meaning in the US, but everywhere I've been in Europe, people use it to just mean "longer minor, 1c with 3-3, 1d with 4-4" as MickyB said. The alternatives being various forms of 2+ 1c or 1d.

I thought it means "1C with 3=3, 1D with 3=2, no idea what partner does with 4=4".

[fromageGB]

"Better minor" is one of those descriptions that should never be used, as a comparative ("better") depends solely on unspecified value judgements. Is AKQ better than 5432 ?

[Trinidad]

A long time ago, I calculated these for our opening system, which is similar to yours. I now recalculated it for your structure.

 

I did the calculation as follows:

• 
   
  
• I assumed (which is not entirely true, but close enough for me) that he number of HCP in the hand and the shape are independent from each other.
  
• I wrote out what distributions open 1♣/1♦
  
• I looked up the probabilities for these distributions in the encyclopedia of bridge
  
• I also looked up the probabilities for the number of HCP in a hand.
  
• I added the probabilities for 11-20 HCPs (for unbalanced hands)
  
• I added the probabilities for 11-14 and 18-19 HCPs (for balanced hands)
  
• For each shape that would open 1♣/1♦, I calculated the probability that it would occur: P=P(shape)*P(in range), with P(in range) depending on whether this shape would open 1/2NT if in the 1/2NT range
  
• In the end, I added the probabilities for the shapes with 3, 4, ..7 clubs/diamonds to get my histogram.
  
• I did not calculate beyond 7 card suits: They are unlikely anyway and often will find another bid than 1m.
  

 

The result is the following table:

 

1♣

cards           probability (%)

3                         19.41

4                         29.72

5                         32.54

6                         15.08

7                         3.23

 

1♦

cards           probability (%)

3                         4.74

4                         43.26

5                         34.39

6                         14.52

7                         3.10

 

This calculation is pretty simple in a spreadsheet.

 

Rik

[Trinidad]

Surely, you meant 3+, not 5+. Or do you have the pleasure of winning part-score battles in a 3-3 fit?

No, he meant 5+. The probability that partner has 3 clubs is significantly reduced by the fact that RHO has a six card major.

 

And competitive bidding is different from constructive bidding.

In constructive bidding, you should always bid based on what partner has promised (i.e. minimum length and strength).

In competitive bidding, you need to get your message across quickly, before LHO takes all your bidding space. This means that you need to base your bidding not on what partner promised (3 clubs), but on what he probably has (5 clubs in jogs view, 4,5 in mine).

 

Obviously, partner should realize that you have already bid based on what he is expected to have. He should not compete more with 4 clubs just because he has one more club than he promised. After all, he has 1 less club than he was expected to have.

 

Rik

[jogs]

Surely, you meant 3+, not 5+. Or do you have the pleasure of winning part-score battles in a 3-3 fit?

 

Yes, I meant 5+. In vacuum 1♣ promises 3+. After opponents preempt conditions change. Granted opener may still have only 3, but it is extremely unlikely.

[aguahombre]

Yes, I meant 5+. In vacuum 1♣ promises 3+. After opponents preempt conditions change. Granted opener may still have only 3, but it is extremely unlikely.

If that translates to bidding 3C after

 

1C (2S) ? with only three of them......wow.

[TylerE]

Probabilties for the following setup?

 

1♣ = 11-13 Bal (No 5M) or 3+ ♣

1♦ = 17-18 (Semi)Bal (5M or 6M322 possible) or 3+ ♦

1M = 11-13 5+M or 11-21 5+M unbalanced

1N = 14-16

2♣ = 19-21 Bal or Any GF+

 

Minor suit opened might be distorted for range considerations if unwilling to rebid longer minor (e.g. 1♣ could be on 2♣+5 bad ♦ if minimum, intending to rebid 1N)

[zenko]

Well the answer is way more complex than that. Your chance of having long clubs when opening 1 club (standard, or standardish) decreases dramatically with each seat. Or in another words if you open 1 club in 1st seat there is a fair chance you actually have real club suit. On 4th seat if you open 1 club you will rarely have 5+ clubs. I actually kept stats on that for a while, in a sample of 3000+ hands 4th seat "real" 1 club opening had less than 1 in 10 occurrence, rest being some kind of balanced hands with 4 or 3 clubs. The cause for that is pretty logical, if you have long clubs most of the time somebody else has long suit too and will usually find a reason to open it in front of you.

[jogs]

If that translates to bidding 3C after

 

1C (2S) ? with only three of them......wow.

 

With only 3 clubs don't you usually have another bid, like double or something. It's not like every hand with only 3 clubs should be bidding 3♣.

[whereagles]

(...) they open 1♣ with 4432 and a 1♦ opening promises 4.

 

that is teh tool of teh Devil!!!!

[Zelandakh]

that is teh tool of teh Devil!!!!

That is probably why they call it Standard American.