Analysis of Beta 1-level Openings
There are 2 main aims in this analysis
Here we make an analysis of each 1-level opening bid in Beta ACOL
Then we will give a theoretical probability for each opening bid
This is the
most frequent of all opening bid so it deserves some mention! It
describes a hand unsuitable for any other system bid:
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.
- Opening 1-level bids focused on in this analysis - about 37%,
however Beta's 1C opening will be up to 9-10% , thats nearly 1 in 10!
1N about 5-6%, and D, H, S each about 6-7% . This all fits well with
the 'theory of information'!
- Other openings: 2C, 2D, 2Ma, 2NT, 3mi (2-suited) - about 6%
- Pre-emptive openings - 2D & 3H and beyond, characterised by weak 6 & 7+ card suit respectively - about 7% of all hands
- PASS the rest: 50% by difference
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.
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%!
Very similar to 1:
needs to be the longest suit and 5 card, 5.5%
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%.
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%
The following defines a Beta 1NT opening:
A 1NT opening works out at about 6%
- 12-14 HCP may be shaded to 11 in 3rd & 4th position openings
- Minor suit holdings MUST total 7 or 8 cards either:
- A 3 card minor must be headed by A, K or Q
- Suit distributions allowed are:
- 4333 (4 card minor)
- 5332 (5-3 card minors)
- 4432 (NOT 4-4 in Majors)
- 2245 (thats 5C & 4D)
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:
- Beta's restrictions on a 1NT opening & ACOL's 1NT
over-belief in its pre-emptive value makes this bid at least 3% more
- Beta's non-adherence to ACOL's principal of 'preparedness'
& ACOL's almost strict adherence-increases Major openings, lowers
frequency of minor openings
- Beta's non-forcing 2 of a Major openings & ACOL's 2's
(mostly through 'Benji' ), Game force opening has a slightly
lower frequency in ACOL
makes weak pre-empts and weak jump overcalls in minors, where Beta does
not:: so pre-emptive opening bids are more frequent in ACOL
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!