Analysis of Beta 1-level Openings

     

There are 2 main aims in this analysis

  1. Here we make an analysis of each 1-level opening bid in Beta ACOL

  2. Then we will give a theoretical probability for each opening bid

PASS

This is the most frequent of all opening bid so it deserves some mention! It describes a hand unsuitable for any other system bid: There is a little shift towards PASS with unfavourable vulnerability say up to 1%, mainly deducted from pre-emptive2openings but not exclusively, otherwise the choices between these 4 groups are well demarcated.
1. 
Beta'a 1C denies a 5+ card suit in any other denomination. Beyond this whatever your HCP for 1NT 1C will be used whenever the restrictions required for 1NT are not present.
Beta's 1C opening is alertable as it cab be just 2 cards.
Many balanced hands with 4 or 5 Clubs & 12-14 will be opened 1NT however the other minor needs to be Hxx  or xxxx and  Majors 4-2  or 4-3. 4-4 in minors will also be opened 1NT with the majors  3-2 & occasionally 4-1 (singleton A or K). However with 5C & 4 D 1NT is opened only when 2-2 in the majors! - otherwise 1C.
12-16 balanced hands (4333, 4432 & 5332, 54xx) will be opened 1  and rebid 1NT where possible AND 17-18 balanced hands with a 2N rebid
With 19+ HCP balanced hands are opened with 2 (19-20) or 2 (23+) or 2NT (21-22).
With 19+ 6 card Club suit or 5Clubs & another 4 card are opened 1 too, upwards until qualifying for a 2 opening with <=3  1/2 LTC.
Estimated frequency of a Beta 1 opening is: 9.8%!

1
Very similar to 1: needs to be the longest suit and 5 card, 5.5%

1
Its very different to the minor's scenario above.
Firstly 5 Card Hearts are opened from 10HCP & with 4-4 in the Majors also  from 10 HCP. Also 5 card majors are never opened 1NT, still some 4 card majors are opened with 1NT or 1C.
With 15-18 a 5+ card 1 is opened if the longest suit and even with 4 cards if and only if the only other 4 card suit is Spades.
5+-4+  Distributions with a 3-4LTC hands are opened 2. 3 1/2 LTC qualifies it for a 2 opening. Also balanced 19-22 hands are opened 2 or 2NT.
Estimated frequency for 1 is 6.5%.

1
Opened if the longest suit or  if 5+ cards there is a second suit of the same length.
As above for Hearts in the range 12-14 a certain number of balanced hands are opened 1NT.
However unlike Hearts, Spades are opened with 10+HCP with 6 + cards (not 2).
15+ are similar to 1, 2, 2 and 2 openings. Except 2S may not have Hearts as a 2nd suit.
Estimated frequency for 1 is 6.5%

1NT
The following defines a Beta 1NT opening:
A 1NT opening works out at about 6%

The overall result is pleasing in that there is a fairly even distribution over 1-level openings. Very different for ACOL where the 5 percentages increase where Beta's decrease! Mainly due to:

The total % for 1-level openings 37%

All these calculations are more complicated than i thought and it has taken more than a full days struggle  and now needs verification over the next  few hundreds of deals by Beta players as there were certain calculations that were guesstimated as so much can depends on vulnerability, support by key middle cards like Ten or Nine & distribution of honours. knowing my habits in doubt I rounded up a bit!