[Knurdler]

Larry Cohen tells me that opening a minor playing Standard American: 1 diamond will be 4 or more cards 97% of the time and 1 club will be 4 or more 83% of the time.

My partner is one of those who insist 1 diamond is 4 cards so we sometimes open 1 club with only 2 cards and announce it as could be short.
Clearly our 4+ diamond percentage rises to 100%.
Can anyone tell me what our 4+ club percentage probability falls to?

Very few here play better minor.
Their better minor means they always open the longer minor but if they are equal length, they open the stronger one.
Can anyone tell me the percentages for 4+ diamonds or 4+ clubs playing this type of better minor?

Thanks

[DavidKok]

Assuming a 15-17 NT, and better minor simply means more HCP in the suit, ties going to clubs, your 1♣ opening is:

• 2 cards: 4.1%
  
• 3 cards: 16.2%
  
• 4 cards: 33.7%
  
• 5 cards: 39.5%
  
• 6 cards: 18.1%
  
• 7 cards: 3.8%
  
• 8+ cards: 0.5%

In my experience most people glance at a table like this and then claim that, regardless of what the numbers are, that it is good enough to disregard the '2 cards' component.
Most five card major systems are really 5543 systems - the 1♠ and 1♥ opening promise 5, the 1♦ opening promises 4, and the 1♣ opening promises 3, and with a 4=4=3=2-distribution outside your NT range you need a systemic lie but it is inefficient to cater to it with the rest of your system. Personally I prefer to make 1♦ 5(+) almost always, which increases the frequency with which 1♣ is two. I think previously(?) the ACBL also had different rules for a 'can be 2' 1♣ opening and an 'always 3+' 1♣ opening, and in that case if you are playing a 5543-system anyway you may as well break ties towards diamonds to get some regulatory protection. But maybe they changed this? At any rate it does to me not matter where you put 4=4=3=2, it's almost entirely symbolic.

[awm]

It’s important to remember, though, that these numbers are not independent from the other distributions at the table. For example, if your partner opens 1♣ and you have 5♣ and want to decide how high to raise, it becomes quite a bit more than 4% that partner has only two and 20% that partner has three or fewer.

[DavidKok]

Conditioning on responder having exactly five clubs I get:

• 2 cards: 8.6%
  
• 3 cards: 25.5%
  
• 4 cards: 35.3%
  
• 5 cards: 24.4%
  
• 6 cards: 5.8%
  
• 7 cards: 0.5%
  
• 8+ cards: 0.0% (after rounding)

If you're a glass half full sort of persion this is a 91+% chance of at least an eight card fit. If you're a half glass empty sort of person this is a more than doubling of the doubleton rate, with almost 35% chance of not having a 9-card fit. At any rate, these are the numbers (using my assumptions for the simulation, which are of course a simplification of real opening criteria).
If you condition on an opponent having an overcall or a takeout double of 1♣ the odds shift in favour of the opening showing actual clubs again, which is probably the most important scenario for deciding when and how high to raise. Giving direct seat overcaller a 1M overcall and responder exactly 5 clubs shifts the odds back again:

• 2 cards: 5.1%
  
• 3 cards: 19.4%
  
• 4 cards: 36.3%
  
• 5 cards: 31.1%
  
• 6 cards: 7.5%
  
• 7 cards: 0.6%
  
• 8+ cards: 0.0% (after rounding)

You decide which table is most informative for the scenario you are thinking of.

[Knurdler]

Thanks for the replies.
Your assumption of 15-17 1NT is valid.
I should have been clearer.

Most people here do not play better minor, so with 4 diamonds and 4 clubs, they always open 1 diamond (regardless of strength imbalance).
They also play 1 diamond must be 4, so with 4432 shape I have to open 1 club with only 2 clubs.
From what I read, this is not the best system but it is what nearly everyone here plays, including better players than me.
So this is the case that I would like the probabilities for.
Is there a website that I can run simulations for myself?

[P_Marlowe]

Knurdler, on 2025-June-03, 09:22, said:

Thanks for the replies.
Your assumption of 15-17 1NT is valid.
I should have been clearer.

Most people here do not play better minor, so with 4 diamonds and 4 clubs, they always open 1 diamond (regardless of strength imbalance).
They also play 1 diamond must be 4, so with 4432 shape I have to open 1 club with only 2 clubs.
From what I read, this is not the best system but it is what nearly everyone here plays, including better players than me.
So this is the case that I would like the probabilities for.
Is there a website that I can run simulations for myself?

https://github.com/d...aler-Version-2-

it also has a minimalistic UI.

[mikeh]

Knurdler, on 2025-June-03, 09:22, said:

Thanks for the replies.
Your assumption of 15-17 1NT is valid.
I should have been clearer.

Most people here do not play better minor, so with 4 diamonds and 4 clubs, they always open 1 diamond (regardless of strength imbalance).
They also play 1 diamond must be 4, so with 4432 shape I have to open 1 club with only 2 clubs.
From what I read, this is not the best system but it is what nearly everyone here plays, including better players than me.
So this is the case that I would like the probabilities for.
Is there a website that I can run simulations for myself?

As someone who has played 1C as 2+ for some 35+ years, my advice is that while simulations can help you work out probabilities of degrees of fit, that’s not the best way to evaluate the method, although understanding distributional frequencies will inform your view of the relative value of 2+ clubs, or 3+, and the optimal way to respond, especially when responder has long clubs.

Firstly, why do so many players, including a large number of experts playing a 2/1 style, play that 1C is 2+? Understanding the benefits helps one to decide whether those benefits outweigh the cost of responder needing to cater to a 2 card holding.

There isn’t a simple answer because different methods of 1C = 2+ provide different costs and benefits.

I started with 2+ clubs only when holding 4=4=3=2, in a strong notrump, 5 card major 2/1 method.

The main advantage, as I saw it, was enhancing our ability to compete in diamonds if we opened 1D. When one opens 1D with 4=4=3=2 and the opps compete, it can be awkward for responder if he holds 3 or 4 diamonds. Obviously this came with a cost in terms of the club suit, but imo it was worthwhile, but not a huge gainer.

Then some 20 years ago I switched to T-Walsh, wherein responder could transfer to a major at the one level…but only after ac1C opening.

Transfer Walsh is, imo, an extremely powerful method, although as always different players play different methods, and imo one variant of the method reduces the advantage of the approach.

In particular, we accept the transfer to hearts or spades with 2-3 cards. Others require 3. The reason we do 2-3 is to allow the sequence 1C 1R 1N to show a hand that would have jumped to 2N. Playing 14-16 1N that means a 1N rebid, after a transfer response, shows 17-19, but if you play 15-17 1N then it’d be 18-19.

This allows us to respond on extremely weak hands if they contain a 5 card major….if opener bids 1N, we transfer and sign off, where others have either to pass 1C (risking an awful fit) of risk going to the 3-level, on minimal values and no good fit. It’s not perfect but we’ve scored a large number of good results from this approach. Plus it gives you a 2N jump rebid to use for something else. If otoh you only accept with 3 card support (both approaches bid at least 2M with 4 card support) then you need 1N as your 12-14 balanced hand. I think that throws away one of the most important benefits of transfers.

More recently, in one partnership, we’ve adopted an unbalanced 1D opening, which has a number of advantages on some hands and some imo lesser disadvantages on others.

In summary….there are modest gains, again imo, from opening 1C with 4432. These gains grow enormously if you ever decide to play transfer responses.

[DavidKok]

T-Walsh is popular here, but swapped out for Dutch Doubleton more commonly at the higher levels. I've played a few variants of T-Walsh for some years and like the variant mikeh describes best of the bunch. I'd argue the convention is good to teach early and therefore appropriate for the forum, but maybe others would disagree.