[blackshoe]

I was just looking at the latest ACBL General Convention Chart, which contains this definition:

Quote

An opening suit bid or response is natural if, by agreement, in a minor it shows three or more cards in that suit, and if, by agreement, in a major it shows four or more cards in that suit.

1♠-2♠. We play Bergen Raises, so our 2♠ is not natural. Of course, we alert it anyway, since it won't have 4 spades. But what if we don't play Bergen Raises? Now 2♠ shows, usually, 3 or 4 spades. Is it natural? Doesn't look like it to me.

[hrothgar]

Hard to disagree with your critique.

With this said and done, what I've always been most confused about is why one should care whether or not a bid is natural or not.

What practical effect does the definition of natural have on the regulatory structure?

Are all "natural" openings legal at some level?
Clearly not...

Can one employ conventional defenses to non-natural bids?
Clearly not...

The whole thing feels like kabuki theater

[ArtK78]

While the language is not precise, I am sure the meaning of the clause that you quoted in referring to a response is a bid in a new suit, not a raise.

As for the 3 cards in a minor suit, I am also sure that refers only to an opening bid of 1 of a minor, not a new suit response in a minor.

[Trinidad]

So, Muiderberg and an Ekrens 2♥ (or Flannery 2♥) are natural?

Rik

[aguahombre]

How sloppy of them for not stating "other than raises"; the world knows it refers to introduction of a new suit.

[blackshoe]

'If "everybody knows" such-and-such, then it ain't so' — R. A. Heinlein

[aguahombre]

 ArtK78, on 2012-April-06, 07:00, said:

As for the 3 cards in a minor suit, I am also sure that refers only to an opening bid of 1 of a minor, not a new suit response in a minor.

You are not correct. It applies to a 1d response to 1C, and to 2c/1X. It also applies to rebids in a minor by opener after opening 1 of a different suit.

[Vampyr]

 blackshoe, on 2012-April-06, 07:22, said:

'If "everybody knows" such-and-such, then it ain't so' — R. A. Heinlein

This time I suspect it is.

[barmar]

Is it news that the GCC and ACBL Alert Chart are extremely sloppy and vague? Perhaps this should be in the Changing forum?

[ArtK78]

 aguahombre, on 2012-April-06, 08:00, said:

You are not correct. It applies to a 1d response to 1C, and to 2c/1X. It also applies to rebids in a minor by opener after opening 1 of a different suit.

Are you trying to tell me that, according to the ACBL, a response of 1♦ or 2♣ showing 3+ in the suit bid is NATURAL? I don't think so.

[aguahombre]

 barmar, on 2012-April-06, 08:25, said:

Is it news that the GCC and ACBL Alert Chart are extremely sloppy and vague? Perhaps this should be in the Changing forum?

It is not news that some of the GCC and of the Alert Chart are sloppy. The chart, for instance is a reasonable attempt to put the Alert regs into neat little boxes for easy reference, and it is definitely imperfect.

But, it takes extra effort to misconstrue what they mean by "natural" in the Section which refers to opening bids, responses, and rebids. It is merely a preamble to other parts which govern whether to alert.

Some natural bids still must be alerted or announced --either because they convey additional meanings, or because ACBL says so.

[aguahombre]

 ArtK78, on 2012-April-06, 08:33, said:

Are you trying to tell me that, according to the ACBL, a response of 1♦ or 2♣ showing 3+ in the suit bid is NATURAL? I don't think so.

Yes, that is what I am telling you. That does not mean they necessarily don't have to be alerted.

[barmar]

Actually, I meant to refer to the Alert Procedures. It's not in little boxes, but it's still very sloppy and overly terse. Many requirements are described by giving a very vague description and a couple of examples, expecting us to generalize from this.

[pigpenz]

Will the GIB robots be forced to bid as the ACBL wants them to?

[barmar]

 pigpenz, on 2012-April-06, 09:06, said:

Will the GIB robots be forced to bid as the ACBL wants them to?

What do they do that isn't allowed by GCC? They're playing a pretty standard 2/1 system.

[blackshoe]

 barmar, on 2012-April-06, 08:25, said:

Is it news that the GCC and ACBL Alert Chart are extremely sloppy and vague? Perhaps this should be in the Changing forum?

Good point. Although I despair of any change coming out of Horn Lake any time soon. I'll move it.

[blackshoe]

 aguahombre, on 2012-April-06, 08:36, said:

It is not news that some of the GCC and of the Alert Chart are sloppy. The chart, for instance is a reasonable attempt to put the Alert regs into neat little boxes for easy reference, and it is definitely imperfect.

But, it takes extra effort to misconstrue what they mean by "natural" in the Section which refers to opening bids, responses, and rebids. It is merely a preamble to other parts which govern whether to alert.

Some natural bids still must be alerted or announced --either because they convey additional meanings, or because ACBL says so.

The alert chart is one thing, the convention charts are a separate issue. Both use essentially the same definitions, it's true. I'm more concerned about why a particular bid should be considered natural (or not) than whether it requires an alert.

I suspect that the reason for these particular definitions is historical, in that under previous versions of the Laws, there were constraints on regulating natural bids, but the laws did not (I think) define which bids are natural.

[aguahombre]

 blackshoe, on 2012-April-06, 09:32, said:

The alert chart is one thing, the convention charts are a separate issue. Both use essentially the same definitions, it's true. I'm more concerned about why a particular bid should be considered natural (or not) than whether it requires an alert.

IMO, it is not important whether something is considered natural unless it is for the purpose of determining disclosure duties. And, that is the context of the ACBL Alert regulations. Maybe certain bids and rebids are not "natural" for discussion with pard or debate with others about system.

But, for the purposes of Alert requirements and disclosure, ACBL has defined "natural", so it can move on from there and tell us what we should do. Once their definition of natural is established, they can save a lot of ink by just using the word in subsequent text.

From the Alert Procedures:

PART I: NATURAL CALLS
Most natural calls do not require Alerts. If the call promises about the expected strength and shape, no Alert is necessary. Treatments that show unusual strength or shape should be Alerted.

As to length, ACBL accepts as NATURAL any offer to play in a suit for the first time that shows:
(1)Three or more cards in a minor suit.
(2) Four or more cards in a major suit.

(Then further down:)

Opener's rebid of two of a minor over partner's forcing or semi-forcing notrump response to a major does not require an Alert if it shows three or more of the suit bid (4-5-2-2 does not require an Alert as long as responder expects three or more cards in the minor).

Two-over-one bids are not Alertable if they are natural and forcing for at least one round.

The fact that you (or I) don't agree with them on what "natural" means in other contexts doesn't seem to be cause for them to change their definition in the Alert regs.

I did not include the GCC references, but the principle is the same.

[barmar]

Yes, I think that's the main reason. But the COMPETITIVE section also says that you can use defenses to conventional calls, but not natural ones. I assume they mean conventional defenses there.

[blackshoe]

The fact remains that a raise of 1M to 2M is not, by the definition in the GCC, natural. So the question is which provision of the GCC makes it legal. I don't see one. Remember, that which (being not natural) is not specifically allowed is disallowed.