Acol

[rienzi]

[blackshoe]

Nobody plays ACOL. There is no such system.

[AL78]

Just saying that the preemptive effect of 1M is a bit lost if its always a strong hand when just being four. Opening a four card 1M when playing strong 1NT is almost as preemptive as opening a weak NT. The "downside" is then when you open 1m with a weak NT and no major (where a weak NT probably would have been better).

 

I have found when playing 5CM strong NT in an Acol field here in the UK that one of the weaknesses of the system is having to open 1m on hands the field is opening 1NT and having the opposition get their major in at the one level when they wouldn't be able to at the two level. The field therefore goes one off in 1NT whilst you get a bottom when your opponents make 2S.

 

One of the good things about Acol weak NT is when partner opens 1suit. They either have at least five of them or a decent hand, which can help responder with judgement if the opponents come in. With 5CM strong NT you have to be a bit careful in competition in case partner has opened with a minimum weak NT hand and again if they could only have a 3 card suit when opening 1minor.

[helene_t]

I have never really understood the theory behind Acol with weak NT and four card majors. Sure, I understand that it is a natural system and therefore it makes sense -- I just don't understand the merits. The best thing about it must be the minor suit openings, which shows a real suit and always extra playing strength. The same could be said about the majors, but the downside is that it is harder to tell about your length.

 

The main benefit (to me) fit four card majors is the preemptive effect of the 1M opening. The opening itself might hinder a lower overcall (or you might open their five card suit). It could also be the case that partner raises and fourth hand is in a tougher spot compared to five card majors. I think a lot of these problems for the opponents disappear if playing a weak NT. Now if opener only has four, he'll have a strong NT. Now the opponents probably don't want to enter the auction anyways. You preempt yourself instead.

 

So with four card majors I'd recommend not opening 1M with a strong NT. I think weak NT fits better with five card majors. The other four card major style is canapé, where you open 1M with 4M and longer side-suit, or 6+M (and maybe some balanced hands).

I would agree with this. But you could also say that strong5 has little merit - after all, if you play 5-card majors it is quite easy to play weak NT so why don't people do that? Basically, people just play what they have been taught, which for historical reasons happens to be weak4 in the UK and strong5 in most other places.

 

4-card majors has the advantage that you don't have to worry about whether you play Walsh or not, since

1m-1red

1NT

denies a 4-card major just by logic, it doesn't require a partnership agreement.

 

Weak NT has obvious benefits.

 

So while there is, IMHO, negative synergy between the benefits of 4-card major and those of weak NT, it's not like either has zero benefits in the context of Acol.

[DavidKok]

For what it's worth, Jan Eric Larsson's "Good, Better, Best" contains summaries of numerical investigation of these systems. He compares these claims through extensive simulations, much more in depth than any other bridge simulation I've seen. About a third of the book is devoted to discussing possible flaws and inaccuracies.

 

His conclusion are that 4cM and 5cM are about equal on balance, but of the 5cM systems the 5533 system is better than 5542 (which itself is a lot better than 5551) and of the 4cM systems the "HCSD" order beats the others, though "HSCD" is not far behind while "CDHS" is noticeably worse. Furthermore, strong notrump is significantly better than a weak notrump in both 4cM and 5cM systems.

[AL78]

4-card majors has the advantage that you don't have to worry about whether you play Walsh or not, since

1m-1red

1NT

denies a 4-card major just by logic, it doesn't require a partnership agreement.

 

Why?

[diana_eva]

Finally, rienzi's necro worked :)

[Cyberyeti]

I would agree with this. But you could also say that strong5 has little merit - after all, if you play 5-card majors it is quite easy to play weak NT so why don't people do that? Basically, people just play what they have been taught, which for historical reasons happens to be weak4 in the UK and strong5 in most other places.

 

4-card majors has the advantage that you don't have to worry about whether you play Walsh or not, since

1m-1red

1NT

denies a 4-card major just by logic, it doesn't require a partnership agreement.

 

Weak NT has obvious benefits.

 

So while there is, IMHO, negative synergy between the benefits of 4-card major and those of weak NT, it's not like either has zero benefits in the context of Acol.

 

This is simply not true. The fact that you play 4 card majors, doesn't mean you always open them. There is a style popularised by Crowhurst that we still play where 4m4M32s are opener the minor, we play 4 card majors mainly because 44(32)s are opened 1♥ rather than a shorter minor.

[helene_t]

Why?

Well, I assume that 4-card majors implies that you always open a 4-card major (if you have one) with 4432 shapes.

 

There are of course styles such as Dutch Acol and Henderson's book in which you open the minor. I don't understand why anyone would play that, IMHO it combines the disadvantages of 4cM with the disadvantages of 5cM. But to each their own.

[Cyberyeti]

Well, I assume that 4-card majors implies that you always open a 4-card major (if you have one) with 4432 shapes.

 

There are of course styles such as Dutch Acol and Henderson's book in which you open the minor. I don't understand why anyone would play that, IMHO it combines the disadvantages of 4cM with the disadvantages of 5cM. But to each their own.

 

It works fine as long as your minors are basically always 4 card suits. There is a style where you play a 4 card heart and 5 card spade, meaning you only open 1♣ on 3 with 4333 15-19. Constructive bidding is actually easier playing this style, you lose out when they can overcall your 15+ hands.

[rienzi]

The defining feature of Acol: 2/1 responses that are 1 round forces only.

You can play 2/1 responses being game force with 4 card major and weak NT,

but this is certainly not an Acol system.

[AL78]

Well, I assume that 4-card majors implies that you always open a 4-card major (if you have one) with 4432 shapes.

 

There are of course styles such as Dutch Acol and Henderson's book in which you open the minor. I don't understand why anyone would play that, IMHO it combines the disadvantages of 4cM with the disadvantages of 5cM. But to each their own.

 

One reason is to avoid wrongsiding a NT contract when you have a strong NT hand, responder has a weak hand and only has 1NT available.

[AL78]

It works fine as long as your minors are basically always 4 card suits. There is a style where you play a 4 card heart and 5 card spade, meaning you only open 1♣ on 3 with 4333 15-19. Constructive bidding is actually easier playing this style, you lose out when they can overcall your 15+ hands.

 

I played that a long time ago with one partner, 5CM in spades only, opening 1♥ promises either 5+ hearts or a four card spade suit.

[rienzi]

The Weak Twos seem to have arrived with the EBU Foundation level 2017. It doesn't mean that they exclude the Strong Twos, the choice is a matter for partnership agreement. The Convention Card is the place for them.

If we abandon the Strong Twos in favour of the Weak Twos then we seriously weaken the structure of the system.

[pescetom]

For what it's worth, Jan Eric Larsson's "Good, Better, Best" contains summaries of numerical investigation of these systems. He compares these claims through extensive simulations, much more in depth than any other bridge simulation I've seen. About a third of the book is devoted to discussing possible flaws and inaccuracies.

 

His conclusion are that 4cM and 5cM are about equal on balance, but of the 5cM systems the 5533 system is better than 5542 (which itself is a lot better than 5551) and of the 4cM systems the "HCSD" order beats the others, though "HSCD" is not far behind while "CDHS" is noticeably worse. Furthermore, strong notrump is significantly better than a weak notrump in both 4cM and 5cM systems.

I am open to the idea that strong notrump is better even with 5cM, but sceptical that 5533 is better than 5542. Where does 5533 gain and how does it outweigh the losses?

[helene_t]

I am open to the idea that strong notrump is better even with 5cM, but sceptical that 5533 is better than 5542 which contradicts my experience. Where does 5533 gain and how does it outweigh the losses?

Probably depends on your follow ups to 1♣. If we sometimes miss a spade fit because 1♠ is fourth suit, or if we play Walsh, I can imagine that 5533 is marginally better. Anyway it surprises me that the difference is big enough to reach statistical significance. Unless he has a sample size of a billion.

[DavidKok]

The difference between flavours of 5cM isn't very big, and he explains that anything under approximately 0.5 IMPs per 24 board match should be dismissed. In the relevant comparison (of 300 24-board matches, so 7,200 boards) the systems scored:

 

5533 +0.67; 4444 HSCD +0.25; 5542 +0.18; 4444 HCSD +0.00; 4444 CDHS -0.43; 5551 -0.68.

 

I would not be surprised if the continuations of 5542 do not resemble modern expert systems, but the book doesn't go into further detail. My personal interpretation is that all these differences are small.

Just for comparison (and because I can't resist), he compares strong (15-17), variable (weak only when NV) and weak (12-14) NT on the same scale:

 

5533 Strong NT +1.67, 4444 Strong NT +0.97, 5533 Variable +0.44, 5533 Weak -0.22, 4444 Variable -1.08, 4444 Weak -1.78.

My interpretation is: the more frequently you play weak NT, the more IMPs you're handing over.

[pescetom]

The difference between flavours of 5cM isn't very big, and he explains that anything under approximately 0.5 IMPs per 24 board match should be dismissed. In the relevant comparison (of 300 24-board matches, so 7,200 boards) the systems scored:

 

5533 +0.67; 4444 HSCD +0.25; 5542 +0.18; 4444 HCSD +0.00; 4444 CDHS -0.43; 5551 -0.68.

 

I would not be surprised if the continuations of 5542 do not resemble modern expert systems, but the book doesn't go into further detail. My personal interpretation is that all these differences are small.

Just for comparison (and because I can't resist), he compares strong (15-17), variable (weak only when NV) and weak (12-14) NT on the same scale:

 

5533 Strong NT +1.67, 4444 Strong NT +0.97, 5533 Variable +0.44, 5533 Weak -0.22, 4444 Variable -1.08, 4444 Weak -1.78.

My interpretation is: the more frequently you play weak NT, the more IMPs you're handing over.

 

Thanks.

 

I was uneasy with Acol 4cM and weak NT, but then I had no idea what I was doing at the time.

I felt more confident with Italian 4cM and strong NT, even better with 5cM and strong NT: never tried 5cM and weak NT yet, have an open mind on it.

 

I briefly played 5533 in two flavours and then switched to 5542 with no regrets.

I agree that the differences are small (especially if 5533 can only be 3 card diamonds with 4=4=3=2) but my tentative conclusion is that they are consistently favourable to 5542 and I find it hard to imagine the contrary.

The book will be part of my reading this summer in any case.

[helene_t]

I haven't read the book, so maybe I shouldn't criticise it :)

 

But it seems to me to be a bit meaningless to compare all those opening schemes if you don't specify in details how the systems are worked out. Maybe the systems are just tuned to strong notrump, for example by a 1NT response to 1x is defined as 5-10 points. Or stuff like inverted minors, shape requirements for 1NT rebids, check-back method, requirements for negative doubles etc etc. Not to mention opponent's overcall style and NT defence. The fact that the analysis is double dummy also means that some of the advantages of aggressive systems are lost.

 

There is much more bidding theory and much more software developed for strong NT than for weak NT. Maybe the results just reflect that?

 

Or maybe opps are very timid in the sims. If opps will rarely interfere over you 1m openings it is obviously better to open 1m than 1NT

[rienzi]

The defining feature of Acol: 2/1 responses that are 1 round forces only.

You can play 2/1 responses being game force with 4 card major and weak NT,

but this is certainly not an Acol system.

 

I don't think this is right. See Standard English Acol, System File 2020. And Beginning Bridge Book One

[Tramticket]

I don't think this is right. See Standard English Acol, System File 2020. And Beginning Bridge Book One

 

It looks a pretty good defining feature to me.

 

Even if we accept that the EBU owns Acol (it doesn't) the Standard English System File that you quote has: "A change-of-suit response at the one level promises at least six points and introducing a new suit at the two level at least 10 points. There is no upper limit. Opener must bid again (unless, exceptionally, responder has already passed).".

 

The requirement for opener to bid again makes the bid forcing and the 10-point requirement is certainly not enough to force to game, so the response is forcing for one round.

[pescetom]

I would say that it is one defining feature.

If it was "the" defining feature, then about half the natural systems in the world including Standard American would be Acol.

[helene_t]

I would say that it is one defining feature.

If it was "the" defining feature, then about half the natural systems in the world including Standard American would be Acol.

Actually, Dutch Acol (strong NT, often played as 5-card majors) is probably identical to what SA would be if played with Acolish forcing character of the 2/1 responses.

 

On the other hand, if you play 2/1 as auto-forcing (as in SAYC and SEF) I don't think many people would refer to the system as "Acol".

[pescetom]

On the other hand, if you play 2/1 as auto-forcing (as in SAYC and SEF) I don't think many people would refer to the system as "Acol".

 

I don't think many people would refer to Italian "Lungo Corto" as "Acol" either, although it shares the key characteristics of 2/1 as a simple force and 4 card major openings, in this case combined with strong NT. In many ways it was a bug-fix of Acol, but nevertheless died abruptly once the Italian variant of 2/1 5cM emerged.

[the hog]

Posters might look at "The Science", a 4 card Major 14-16 2/1 system. It is fun.For many years, beginning with Baronised Acol. a 2/1 was forcing to 2NT. Very few play that responder does not need to bid again.