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Conventions over 1NT openings ACBL

#1 User is offline   astralvic 

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Posted 2014-July-31, 08:07

I've been wanting to start playing a NT with two possible ranges (we'll say 10-12 and 18-19 to make things simple).
After a reading of the ACBL General Convention Chart, the only reference I can find to two non-consecutive ranges is RESPONSES AND REBIDS, 10:

Quote

ALL CALLS AFTER A NATURAL NOTRUMP opening bid or direct overcall, EXCEPT for natural notrump opening bids or overcalls with a lower limit of fewer than 10 HCP or with a range of greater than 5 HCP (including those that have two non-consecutive ranges).


This leads me to believe that my 1NT opening would indeed not only be legal, but that I'd be able to play anything over it. Am I correct in my thinking? Or have I missed anything somewhere?

In addition, am I able to open a 1NT (and play conventions) when the 1NT meets the following criteria? (case-by-case)
  • 10
  • 10 OR 12
  • 10-14
  • 10-13 VUL; 13-16 NON-VUL
  • 24-26
  • 10-11 OR 15 OR 18-19


Thanks. :)
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#2 User is offline   WellSpyder 

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Posted 2014-July-31, 08:13

I'm not an expert on interpreting ACBL-speak, but I would describe 10-12 OR 18-19 as a range of greater than 5 HCP, even though it only includes 5 possible HCP counts.
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#3 User is offline   RMB1 

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Posted 2014-July-31, 08:17

I think the intention is that 10-12 or 18-19 is a 10-point range (the same as 10-19) so no artificial responses are allowed.
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#4 User is offline   astralvic 

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Posted 2014-July-31, 08:18

View PostWellSpyder, on 2014-July-31, 08:13, said:

I'm not an expert on interpreting ACBL-speak, but I would describe 10-12 OR 18-19 as a range of greater than 5 HCP, even though it only includes 5 possible HCP counts.

To add on to that, if you play 10-12 NONVUL and 15-17 VUL, would that be legal? At any one time, you only have a range of 3 HCP, but there are a total of 6 point-count ranges you can open 1NT with, as well as a total of 8 point-count ranges between your lowest and highest openings (10, 11, 12, 13, 14, 15, 16, 17)
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#5 User is offline   RMB1 

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Posted 2014-July-31, 08:21

The ACBL could use its regulatory powers under 2008 laws to regulate wide-ranging natural NT bids - rather than the circumlocution of regulating the responses.
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#6 User is offline   helene_t 

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Posted 2014-July-31, 08:27

According to wikipedia, the word "range", in statistics, means the difference between the extreme value, while in mathematics and computer science it is the size of the set. I.e. you could get away with it if the TD is a mathematician or computer scientist but not if he is a statistician.

I may be biased because I am a statistician myself but I think you won't get away with it. Presumably the reason why ACBL wants to discourage wide-ranging notrump ranges is that it becomes murky whether opps should use a constructive or an obstructive defense. For that purpose, 12-14 or 18-20 is almost as annoying as 12-20.

I would think that a variable range, depending on vulnerability and/or seat, would be ok.
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#7 User is offline   jeffford76 

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Posted 2014-July-31, 09:47

View PostRMB1, on 2014-July-31, 08:17, said:

I think the intention is that 10-12 or 18-19 is a 10-point range (the same as 10-19) so no artificial responses are allowed.


Yes, this is the correct interpretation. Note that this is per seat/vulnerability. If you want to play 10-12 white and 18-19 red for example, this would be fine.
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#8 User is offline   PrecisionL 

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Posted 2014-July-31, 11:05

View Postastralvic, on 2014-July-31, 08:18, said:

To add on to that, if you play 10-12 NONVUL and 15-17 VUL, would that be legal? At any one time, you only have a range of 3 HCP, but there are a total of 6 point-count ranges you can open 1NT with, as well as a total of 8 point-count ranges between your lowest and highest openings (10, 11, 12, 13, 14, 15, 16, 17)

Yes, ACBL allows NT range to change with vulnerability and/or position.

You are allowed to play two non-consecutive ranges.

If the range of 1NT is "greater than 5 hcp (including those that have two non-consecutive ranges)", no conventions are allowed in response to 1NT by the opening side.

General Convention Chart, 2/14 #520226, http://web2.acbl.org...ntion-Chart.pdf

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#9 User is offline   chrism 

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Posted 2014-July-31, 11:20

The Mid Chart regulations prohibit:
conventional calls after natural notrump opening bids or overcalls with a lower limit of fewer than 10 HCP or with a range of greater than 5 HCP (see #10 under RESPONSES AND REBIDS and #7 under DISALLOWED on the General Convention Chart) – however, this prohibition does not extend to notrumps that have two non-consecutive ranges neither of which exceeds 3 HCP
which does not particularly help to clarify the GCC regulation but does mean that you can play conventional methods over your split-range NT in Mid-Chart events. If you want to use it in a club, check before the game with the club manager or director, since clubs have freedom to make their own restrictions on conventions, and vary considerably.
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#10 User is offline   blackshoe 

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Posted 2014-July-31, 12:58

I would never have expected that the ACBL intends the two non-consecutive regions 10-12 and 18-19 as a ten point range. Rather, I would read it as 10-12 is 3 points, and 18-19 is two points, total, 5 points. I know of no interpretation, precedent, case law, or what have you, that indicates this range should be interpreted as ten points (save what has been posted here, which really surprised me). That includes (from memory, I haven't looked just now) the tech files. That said, given the wonderful clarity, tranparency, and availability the ACBL brings to their regulating function, I wouldn't be at all surprised to find I'm wrong.

Re: the Mid-Chart regulation: 10-12 is 3 points, 14-16 is 3 points. Given Robin's interpretation of the GCC regulation, this is a 7 point range, which would be illegal under the Mid-Chart except for the "neither of which exceeds 3 points" exception. I suppose this could be read as implying that under the GCC regulation it should be interpreted as a 7 point range (and hence illegal under the GCC). But it doesn't make sense to me.
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#11 User is offline   jeffford76 

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Posted 2014-July-31, 14:31

Certainly the regulation could be better phrased as something like "... or with a difference between the minimum and maximum point count greater than 5 HCP ...".
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#12 User is offline   chrism 

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Posted 2014-July-31, 15:50

See also the earlier discussion: http://www.bridgeba...60530-1n-range/

This post has been edited by barmar: 2014-August-01, 10:37
Reason for edit: Fix URL

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