1m opening length probabilities
#1
Posted 2014-February-05, 18:50
What is the probability that partner has 3 cards/4 cards/5+ cards when he opens 1C? And likewise when he opens 1D?
Thanks.
#2
Posted 2014-February-05, 19:11
MickyB, on 2014-February-05, 18:50, said:
Q. If you are playing 1C on 3-3, 1D on 4-4, can you still play better minor?
#3
Posted 2014-February-05, 20:03
MickyB, on 2014-February-05, 18:50, said:
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.
#4
Posted 2014-February-05, 23:09
PeterAlan, on 2014-February-05, 20:03, said:
Ok let's say 11-21 unbal/12-14 bal/18-19 bal. Assume 5m422 in range opens 1NT. Thanks
#5
Posted 2014-February-05, 23:13
glen, on 2014-February-05, 19:11, said:
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.
#6
Posted 2014-February-05, 23:45
MickyB, on 2014-February-05, 23:13, said:
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♣
a.k.a. Appeal Without Merit
#7
Posted 2014-February-06, 01:09
awm, on 2014-February-05, 23:45, said:
♠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.
#8
Posted 2014-February-06, 09:26
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.
#9
Posted 2014-February-06, 09:38
karlson, on 2014-February-06, 01:09, said:
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?"...
#10
Posted 2014-February-06, 10:51
MickyB, on 2014-February-05, 23:09, said:
Basis:
- Concerned only with 4-3-3-3 to 6-6-1-0 shapes; all 7+ suit hands excluded
- 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)
- All 11-21 unbalanced opened (including 11 HCP 4-4-4-1)
- 5-5 or 6-6 M-m open M; 6-5 m-M open m
- 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:
- 25% of 4-3-3-3 hands open 1♦ (4 card), 25% 1♣ (4 cards) and 50% 1♣ (3 cards)
- 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)
- 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):
- There are 234,166,911,312 1x opening hands in this sample space
- 34,297,838,856 (14.65%) open 1NT and 77,785,551,954 (33.22%) 1M
- 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
- 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!
#11
Posted 2014-February-06, 15:45
#12
Posted 2014-February-07, 07:12
Free, on 2014-February-06, 09:38, said:
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.
#13
Posted 2014-February-07, 08:21
jogs, on 2014-February-06, 15:45, said:
Surely, you meant 3+, not 5+. Or do you have the pleasure of winning part-score battles in a 3-3 fit?
#14
Posted 2014-February-07, 08:33
#15
Posted 2014-February-07, 08:33
karlson, on 2014-February-06, 01:09, said:
I thought it means "1C with 3=3, 1D with 3=2, no idea what partner does with 4=4".
#16
Posted 2014-February-18, 16:45
#17
Posted 2014-February-19, 07:10
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
The most exciting phrase to hear in science, the one that heralds the new discoveries, is not “Eureka!” (I found it!), but “That’s funny…” – Isaac Asimov
The only reason God did not put "Thou shalt mind thine own business" in the Ten Commandments was that He thought that it was too obvious to need stating. - Kenberg
#18
Posted 2014-February-19, 07:23
aguahombre, on 2014-February-07, 08:21, said:
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
The most exciting phrase to hear in science, the one that heralds the new discoveries, is not “Eureka!” (I found it!), but “That’s funny…” – Isaac Asimov
The only reason God did not put "Thou shalt mind thine own business" in the Ten Commandments was that He thought that it was too obvious to need stating. - Kenberg
#19
Posted 2014-February-19, 10:07
aguahombre, on 2014-February-07, 08:21, said:
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.
#20
Posted 2014-February-19, 12:27
jogs, on 2014-February-19, 10:07, said:
If that translates to bidding 3C after
1C (2S) ? with only three of them......wow.