DIP: 0.2.2

Cogitare, Constituere, Conficere!

Below is the new front page for DIP.  It will contain the system and ideas contained that have been discussed in the blog.  The other posts in the blog will be in reverse chronological order, so the most recent post is the next one down.

Openings Bids (1st/2nd Seat)

• 1♣::  ART, STR, 15.0+ fpc
• 1♦::  4+♥, 10.0 to 14.8 fpc:  inc 4♥5m but not 4♥6+m, inc 4♥4♠, not ♥<♠ unless 4♥5♠4m, not 3433
• 1♥::  4+♠, 10.0 to 14.8 fpc:  inc 4♠5m but not 4♠6+m, inc 5+♠5+♥, ♠>=♥, not 4333
• 1♠::  5+♦, 10.0 to 14.8 fpc:  usually 6+♦ (unless 5+♦4+♣), inc 6+♦4M, not 2254
• 1NT::  BAL, 12.0 to 14.8 fpc:  inc 5m4m22, no M unless 4M333
• 2♣::  5+♣, 10.0 to 14.8 fpc:  usually 6+♣ (unless 5+♣4♦), inc 6+♣4M, not 2245
• 2♦::  4+♠, 6.0 to 9.8 fpc:  long pointed, short round, “Jammer”:  4-5♠, 3-5♦, 3-5 RND, 0-2 O-RND
  
• 2♥::  4+♥, 6.0 to 9.8 fpc:  long round, short pointed, “Jammer”, 4-5♥, 3-5♣, 3-5 PTD, 0-2 O-PTD
• 2♠::  5♠, 6.0 to 9.8 fpc:  5♠332 or 5♠4m22

Openings Bids (3rd Seat)

• 1♣::  ART, STR, 17.0+ fpc
• 1♦::  0+♦, 11.0 to 16.8 fpc:  inc 4♦5♣, if BAL then 11.0 to 13.8 fpc
  
• 1♥::  5+♥, 11.0 to 16.8 fpc: 
  
• 1♠::  5+♠, 11.0 to 16.8 fpc: 
  
• 1NT::  BAL, 14.0 to 16.8 fpc:  not 5M332, inc 5m422
  
• 2♣::  6+♣, 11.0 to 16.8 fpc:  inc 6+♣4M
• 2♦::  4+♦, 0.0 to 10.8 fpc:  long diamond “Jammer”, 4-5♦, 3-5X, 3-5Y, 0-2Z
  
• 2♥::  5-6♥, 0.0 to 10.8 fpc:  6♥322, 5♥332 or 5♥422
• 2♠::  5-6♠, 0.0 to 10.8 fpc:  6♠322, 5♠332 or 5♠422

Openings Bids (4th Seat)

• 1♣::  ART, STR, 17.0+ fpc
• 1♦::  0+♦, 11.0 to 16.8 fpc:  inc 4♦5♣, if BAL then 14.0 to 16.8 fpc
  
• 1♥::  5+♥, 11.0 to 16.8 fpc: 
  
• 1♠::  5+♠, 11.0 to 16.8 fpc: 
  
• 1NT::  BAL, 11.0 to 13.8 fpc:  not 5M332, inc 5m422
  
• 2♣::  6+♣, 11.0 to 16.8 fpc:  inc 6+♣4X
• 2♦::  6+♦, 14.0 to 16.8 fpc:  good suit, usually KQxxxx or better
• 2♥::  6+♥, 14.0 to 16.8 fpc:  good suit, usually KQxxxx or better
• 2♠::  6+♠, 14.0 to 16.8 fpc:  good suit, usually KQxxxx or better

Definitions & Abbreviations

Where possible, definitions will conform to WBF Abbreviations, a copy of which can be found here

http://www16.plala.or.jp/KOKO33/system/abbrevi.html

In addition, there are the following

• fpc:  “Fifths Point Count”:  (A=4.0, K=2.8, Q=1.8, J=1, T=0.4), Note that fcp ≈ hcp = both 40 point decks
• inc:  “Includes”:  normally meaning it includes the subsequent hand shape

Version Control Log

• 0.2.2::  Added in the motto “cogitare, constituere, conficere”
• 0.2.1:: Changed the 2♦ Jammer opening in 3rd seat to guarantee 4-5♦ (rather than 3-5)
• 0.2.0::  Added in weak range openings up to 2♠
• 0.1.0::  Added in 3rd and 4th seat strong and intermediate range openings as described in 30/10/2008 blog.
• 0.0.0::  First version of system using “fpc”:  Earlier information from the blog also included.

DIP: Ace and King Parity Revisited

Welcome to 2009! It’s been a month since my last blog, so I thought it was time I got back on the horse.

Over the festive season, whilst travelling and hanging about in airports, I’ve been revisiting my earlier thoughts on Control Showing. You may recall, I raised three questions about the JVCB method which I was proposing to somewhat emulate

1. When to STOP or GO when showing A and/or K parity (and why)
2. Why, in pure JVCB, A/Q’s are first considered in 5+ suits, whereas K’s are considered in 4+ suits
3. Why scan K’s before A/Q’s

I am still no closer to answering (2), but have some of an idea about (1) and (3) now, I believe.

With respect to (1), “Expected Parity”, as described in the previous blog, seems to work pretty well. It averages (from memory) 0.83 steps (where GO then GO is 0 steps and STOP then STOP is 2 steps) through the A and K parity phase. This is good when you consider that “Optimum Parity” (i.e. remembering the best combination by wrote) only gets you the marginal improvement average of 0.76 steps through the phase.

There are, however, at least two other considerations.

The first, raised by SD, is why commit to a pre-determined “opinion” on K parity before knowing A parity? It’s a fair question and one I hadn’t previously considered. I haven’t got around to modelling a post-facto choice on K parity based on expected A parity, but there is a reason for this – see below.

The second consideration is whether it is right to consider A parity first, or whether K parity might be the better option. Indeed, there are some in Australia who have considered adding a K parity step to more standard DCB methods because of its apparent value in determining “control structure” (by which, I mean the number but not explicit location of A’s, K’s and Q’s respectively in RR’s hand).

I think there may be some merit in K parity before A parity (but still keeping both asks). The reason I believe this is that I expect the answer to the K-parity question is more likely to be immediately beneficial (in guaranteeing or ruling out the safety of another ask). Why? Because I expect that knowing/deducing the number of K’s is more likely to give an immediate picture of the complete control structure than the number of A’s (because of needing a specific number of A’s to make up the known QP count, or because there are insufficient free Q’s, remember, singleton Q’s are treated as J’s, to permit some combinations). I would guess this rationale is largely behind the adoption of the idea by those who have done so in Australia.

To merge these two lines of thought into a solution, then, I need to

1. Determine the best way to model “Expected King Parity for given QP’s” (which will likely be a compromise between memory and efficiency)
2. Determine the best way to model “Expected Ace Parity based on known King Parity for given QP’s”

Some previous K parity work by others has suggested that GO=ODD for K parity on 2 and multiples of 3 QP’s (otherwise GO=EVEN) is a good mnemonic and quite efficient. It doesn’t work for 15 QP’s, but that isn’t too much of a problem! I have a suspicion that this (2 and multiples of 3) is where we might end up.

Working out what to do with A parity after that start will require some serious number crunching I expect.

I think a related rationale to that above is behind the showing K’s before A/Q’s when showing specific honours.  I’m still thinking about that, however.

Regards, DipBridge

DIP: Control Showing

I’m using WIndows Live Writer for the first time with this blog – let’s see how it goes.  One advantage is that the editing window is far bigger than that provided by default on the WordPress site, which should help for the kind of content of this blog.

Whilst continuing to procrastinate on aspects of DIP, I delve back into others.  This blog assumes some knowledge of relay methods and the need to have a structure for showing controls (whether A=2 or A=3 based).  If you are newer to relay methods, don’t worry about this blog too much for the minute – come back to it when the time is right.

SD and I have discussed the merits of many different possible methods for DIP’s use.  Currently, I favour basing DIP’s method on a Scandanavian method known as JVCB.  This is more difficult than it sounds, because I have an imperfect knowledge of the rationale behind some aspects of JVCB.  For those familiar with the method, this leads me to question and/or change three things

1. Whether to STOP on EVEN when showing Ace parity (and similar considerations for when showing King parity)?
2. Why are A’s & Q’s considered first only in 5+ suits, rather than the outwardly more intuitive 4+ suit option?
3. Why are K’s scanned before AQ’s?

My current ideas with respect to the above three considerations are

1. To try and optimise when to STOP & GO with the parity methods.
2. To switch to showing A’s & Q’s with 4+ suits first (but quite willing to change back to the JVCB default if and when I understand 5+ to be meaningfully superior – any help here appreciated).
3. No change.  Though I don’t understand the rationale (yet at least) maybe there is less information needing to be exchanged this way around, so maybe the reason is that the key to the hand may unlock more quickly showing K’s first.

OK, so how to optimise when to STOP and when to GO when showing A and K parity?  Whenever I have seen parity like methods, they for some reason seem to default to STOP = EVEN and GO = ODD.  SD has done some work with others on optimising K-parity, resulting in something that is difficult to remember, and consequently when used is watered down to an easier to remember form (doing something different with 2QP’s, or multiples of 3 QP’s).  Let’s try and figure out something different that is hopefully easily remembered OR derivable from first principles.

Intuitively, for a given number of QP’s (i.e. an A=3 based control count) which I intend DIP to use by default, the following seem likely to be the most frequent top honour structures, with their proposed GO showing parity steps following

• …
• 4: AQ (most likely, as opposed to KK or KQQ or QQQQ) … so GO = ODD (expecting 1) ace and GO = EVEN (expecting 0) kings
• 5:  AK … so GO = ODD aces and GO = ODD kings
• 6:  AKQ … so GO = ODD aces and GO = ODD kings
• 7:  AKQQ … so GO = ODD aces and GO = ODD kings
• 8:  AKKQ … so GO = ODD aces and GO = EVEN kings
• 9:  AAKQ … so GO = EVEN aces and GO = ODD kings
• 10: AAKQQ … so GO = EVEN aces and GO = ODD kings
• 11:  AAKKQ … so GO = EVEN aces and GO = EVEN kings
• 12:  AAKKQQ … so GO = EVEN aces and GO = EVEN kings
• …

As a guideline to building the above, it is intuitively assumed that

• AKQ (dispersed somewhere within the hand) is a more likely honour structure than KKK, and similarly
• AK is more likely than KKQ
• AQ is more likely than KK
• A is more likely than KQ

That is, to take an overly simplistic example, where H means one of A or K or Q, for a six QP hand, Hxxx Hxx Hxx xxx is (maybe six times) more likely than specifically Kxxx Kxx Kxx xxx.  I hope to be able to confirm this intuition either empirically or theoretically at some point.

I applied this theory to some statistics on parity that SD has previously generated for the 4 to 12 control range.  It appears to work well.  There was an insignificant blip on 8 QP’s for Ace parity (49% versus 51%) and minor blips on 7 QP’s and 12 QP’s for King parity (42% versus 58% and 45% versus 55% respectively).

I’m therefore comfortable with pursuing the above as a working hypothesis as when it is right it is often really right (into the 60%’s or 70%’s).  Let’s call the parity determined from the intuitively most likely case as “Expected Parity” or “EP”.  One key good thing about it is that you don’t have to remember it if you don’t want to – you can derive it from first principles easily when needed.

Knowing that one has a good theory/hypothesis is only part of the work, it remains to decide how to apply it.  There are, to my mind, two options

1. Use it to maximise the number of hands where no stops are required during the Ace-parity and King-parity phases (i.e. you GO then GO), or
2. Use it to minimise the number of hands where two stops are required during the Ace-parity and King-parity phases (i.e. you don’t STOP then STOP again).

To satisfy design criteria (1), one would have the Ace and King parity phases targeted at their “Expected Parity”.  That is, for a 6 QP hand you would STOP on EVEN ace parity (expecting to GO) and STOP on EVEN king parity (once again, expecting to GO) as described in the earlier tabulation.

Part of the reason at present not to aim instead at design criteria (2) is that it is not clear how to achieve it with a simple rule.  My best guess, which I will try when I do further statistical analysis, is to go for EP with Aces and the opposite of EP with Kings.  The reason for this is more readily apparent with lower QP count hands.  If a 3QP hand doesn’t have the Ace predicted by EP, it is far more likely to be KQ than QQQ, so if forced to STOP with no Ace you would then want to GO with one King if aiming to satisfy design criteria (2).  Intuitively, however, I would expect this reverse correlation to lessen slightly for higher QP counts where an Ace might indeed be replaced by three queens.  Hence, only some form of statistical analysis will suffice to confirm or refute this.

Subject to all the above, the rest of DIP control showing is currently planned to work according to my (possibly imperfect) understanding of the JVCB method, as outlined in phases (or “passes’) below

• Determine your QP count (known as ZZ controls in JVCB), A=3, K=2, Q=1, singleton K = 1 (subsequently treated as a Q) and singleton Q = 0 (subsequently treated as a J)
• Show Ace-parity derived from your QP count (GO = EP, STOP = not EP)
• Show King-parity derived from your QP count (GO=EP, STOP = not EP)

Having done the above, it is assumed (occasionally without merit) that partner can derive your exact honour structure (but not necessarily which suits they are in).  Even if he can’t, he may be able to reduce it to a limited number of possibilities and be able to gamble on the percentages if space becomes short.

After that, we intend to scan through the following phases in order, subject to the rules mentioned after

1. K’s in 4+ card suits (STOP = no K, GO = K)
2. A’s and/or Q’s in 4+ card suits (STOP = neither or both AQ, GO = A or Q only)
3. K’s in 2 to 3 card suits (STOP = no K, GO = K)
4. A’s and/or Q’s in 1 to 3 card suits (STOP = neither or both AQ, GO = A or Q only)
5. J’s (STOP = no J, GO = J)
6. Singleton J’s (STOP = no J, GO = J)

The clarifying or modifying rules are

• Scan longest suits first
• Scan lowest suits first when equal length
• Assume partner knows exactly what you’ve shown*, skipping subsequent bids accordingly, see examples inbuilt in some of the points below
  • If you have NO or ALL Kings that you might have (where ALL is 4 for balanced hands, or 3 for hands with a shortage – remember singleton K is treated thereafter as a Q) completely skip phases (1) and (3) above. As per the bullet point above, partner is assumed to know OR will figure it out as soon as a subsequent scanning anomaly reveals it.
  • Similarly, if you have NO or ALL the AQ’s you might have, completely skip phases (2) and (4) above.  For clarity, ALL means 4 aces and 3 queens when holding a singleton.
  • Similarly, if you have ALL Aces and NO Queens (or vice-versa) skip phases (2) and (4).
  • If you have NO or ALL Aces and some Queens (or vice-versa) ignore the NO or ALL one and scan the other one in the King scanning style.
  • Ignore thereafter a suit at all with no free slots (i.e. a void, or a singleton where an honour has been shown or implied)
  • Never scan the last suit with unknown cards during a phase, R is assumed already to know the answer*.

A couple of examples to illustrate the asterisked points above.  Assume you have shown 4441 with 5 QP’s and ODD king parity.  If your King is in diamonds, you show it and then move immediately to AQ scanning – you can’t have another K.  Similarly, if your King is in spades, you deny it in diamonds then deny it in hearts, then move immediately to AQ scanning – partner knows where it must be.

There’s bound to be a mistake, a typo or a mild misunderstanding somewhere above as it’s a fairly complex area (but elegantly simple once you get your head around it).  I’ll correct such things in-situ when I find them.

UPDATE:  I’ve done the number crunching on a million hands a time (thanks to Andrews’ Deal program again) and it seems my intuition was fairly much right.  That is, if you go for design criteria (1) and aiming your parity to match both A’s and K’s with their EP, you get

• Zero stops :  47%
• One stop:  24%
• Two stops:  29%

However, if you go for my guessed solution to design criteria (2) where you match A’s and mismatch K’s with their EP (hoping to get a K match when the A’s value is wrong), you get

• Zero stops:  14%
• One stop:  76%
• Two stops: 10%

So, for a 33% percent loss of zero stops you gain 19% of the two stops back.  It doesn’t seem good value to me, so I am going to stick with my original idea and aim for design criteria (1).

To set a reference point for both the above sets of figures, I have done the stats on the “standard” STOP EVEN, GO ODD approach to parity.  It is self-evidently fairly poor, as you will see from the results below

• Zero stops:  24%
• One stop:  47%
• Two stops: 29%

With reference to all the above statistics, I have ignored the fact that singleton K’s will be treated as Q’s and included them for purposes of this particular analysis. I’ll try and refine this and other aspects of the analysis further in due course, but I wouldn’t expect it to meaningfully alter the apparent lessons.

Regards, DipBridge

DIP: Responding to 1NT [IV - Overview of 1st round responses]

I was going to write a much longer post than this, but I’ll split it up.  Here is the full set of first round responses

• 2C:  STAY
• 2D:  TRF to H
• 2H:  TRF to S
• 2S:  TRF to C (WK or STR, 1/S or 2/S with 5+D)
• 2NT:  TRF to D (WK or STR, 1/S or 2/S with 5+C)
• 3C: 5+m/5+m, INV
• 3D:  5+m/4+m, FG
• 3H:  3/S short S, not 5H, FG
• 3S:  3/S short H, not 5S, FG
• 3NT:  to play
• 4C/D:  S.A. Texas, little slam interest
• 4H/S/5C/D:  NAT, to play
• 4NT:  Blackwood

At this point, I will note one quirk to the continuation structure (there will be more later, no doubt).  In response to the 2S and 2NT minor suit transfers, opener should bid “step” and NOT accept the transfer when

• He has 4-5 cards in the other minor, and
• The other minor is longer than the “transfer” minor

This structure allows WK 5m/4m hands to be handled sensibly, guaranteeing a minimum 8 card and non-inferior fit.  Also, handling the WK one and two suiters in one bid importantly frees up 3C to handle the INV 5+m/5+m types.  Nothing else I could come up with works this elegantly.

The overall structure seems relatively simple and obvious – why did I agonise so much over it?  Well, I think that will become apparent as the continuations are more fully described.  Nevertheless, it probably serves well now to consider the design criteria, which, in no particular order are

1. To ensure we can R(elay) to obtain exact shape before breaching a safety level.  In most instances this safety level will be 3NT.
2. In addition to (1) above, we would also like at least one range clarifying control (QP) ask at or below 3NT.
3. To ensure we have an alternative to relaying with strong & shaped hands.  Such hands will contain a singleton, void and/or 6+ card suit.  In this case of the singleton or void, this will allow opener to accurately value his honour dispersion opposite the known shortage.  In the case of the 6+ card suit, it will enable opener to consider his honour fit opposite a known long suit that is possibly in a marginal slam hand.
4. In addition to (3) above, we want these strong & shaped hands to be described before breaching a safely level.  Once again, this will often be 3NT, but might be 4H, 4S, 4NT, 5C or 5D also.  In long minor hands when showing shape past 3NT, both 4NT and 5m are considered safety levels and sign-off attempts, if bid.
5. To allow opener to anti-SPL (i.e. show concentrations of values, particularly lower honours) and responder to SPL in strong shape showing sequences wherever possible.
6. To minimise 1st round ambiguity in responders shape(s), such that if the opponents compete, the degree of fit is fairly clear, if not the strength.
7. In achieving (1) to (6) above, to minimise the number of our preferred invitational sequences, which we have previously identified, that need to be given up or bastardised.

We have already pretty much ensured (1) with the STAY structure and continuations.  3H will be reserved over the 2M responses as R (allowing 3NT to show B or B+1 controls, and 3S >= B+2 controls) satisfying design criteria (2) in the process.  2H is reserved as R over the 2D response to STAY, with the following RR responses

• 2S::  both m’s, then after 2NT R
  • 3C:  2344
  • 3D:  3244
  • 3H:  2245
  • 3S:  2254, >=B+2 QP’s
  • 3NT:  2254, B or B+1 QP’s
• 2NT::  5C332, then after 3C R, similar to 5D332 from 3D+ below
• 3C::  4m333, then after 3D R
  • 3H:  3334
  • 3S:  3343, >= B+2 QP’s
  • 3NT:  3343, B or B+1 QP’s
• 3D::  2353
• 3H::  3253
• 3S::  3352, >= B+2 QP’s
• 3NT::  3352, B or B+1 QP’s

As you can see, we haven’t quite satisfied design criteria (2):  4 of 12 shapes don’t get a range clarification below 3NT – this is the cost of including the 5m4m22’s and 4M333’s into the opening.  On balance, however, I think it’s worth it – the 4M333’s feel like they belong (and it gives 1D and 1H more offensive sting).  The argument is less clear for the 5m4m22’s – they certainly don’t look out of place in 1NT though that argument is not as compelling as for the 4M333’s.  However, they do make the 1S and 2C openings work significantly better from both an offensive and R perpective, so I think the choice can be justified.

Until next time.

Regards, DipBridge.

DIP: Responses to 1NT [III - A brief respite for a motto]

Bless me WordPress, for I have sinned.  It’s been over two weeks since my last blog …

Since it has been a while (I won’t regale you with the excuses) just a quick recap to sum up where we were after the last “Responding to 1NT” blog.  So far, the key parts (mainly INV) of the response structure to 1NT look like

• 2C:  STAY
  • ART FG R or BAL (near-BAL) no M INV, or
  • 4S &/or 4H INV, or
  • 5S maybe with 4H INV, or
  • 5+m maybe with 4M INV
• 2D:  TRF to H
  • WK H, or
  • 5H maybe with 4S INV, or
  • 5H with 4+m INV, or
  • some other strong hands as yet not spelled out
• 2H:  TRF to S
  • WK S, or
  • 5S & 5H INV, or
  • some other strong hands as yet not spelled out

Finally, I have been thinking of a motto to try and encapsulate the approach with DIP.  After consulting some experts, I have gone with

cogitare, constituere, conficere

There’s a nice bit of Ciceronian alliteration in it, not simply with the first letter, but also with the final one.  However, that’s not the reason:  it’s my preferred translation (of the phrase “Calculate, Determine, Execute”) from the ones offered.  It’s literal piece by piece translation is closer to

think, set-up, realise

but I think it gets the idea across as a whole.

Regards, DipBridge

DIP: 2D “Jammer” in 3rd Seat

Hmm.

I’ve been doing some simulations, and, discretion’n'valour and all that, I’ve provisionally decided to amend it so that this particular Jammer instance shows 4-5D rather than 3-5D.

Playing it as 3-5D had the power to be immensely destructive, but hard to handle (i.e. finding our best fit) if we’re in trouble.  This suggests to me that a 3-5D treatment might work OK as a “bunny-bashing” device, but maybe not so hot against decent and organised opposition.  I’ve always preferred to design my systems to face the latter category, hence the choice.

I am also conferring with SD as to whether there is any merit, in 4th seat in particular (and maybe even 3rd seat, though it would lose the above Jammer) as playing 2D as simply 11.0 to 16.8 6+D rather than 14.0 to 16.8 6+D good suit.  This is because the 1D opening itself is now fairly nebulous in 3rd/4th seat.  I am awaiting SD’s considered response on this one:  it is normally worth the wait.

In the meantime, I’ll adjust the system page to reflect the amendment to the 3rd seat 2D opening.

Regards, DipBridge

DIP: Opening Bid Frequency

A first for DipBridge:  two blogs in one day!

Fleshing out the weak range opening bids (excluding, for the present, 2NT and higher pre-emptive openings) allows me now to do a fairly accurate (subject to my programming errors and therefore subject to revision) analysis of the frequency of opening bids.  Thomas Andrews deal programme has been invaluable thus far for this purpose.

Here is the output, based on 1,000,000 deals, for DIP 1st/2nd seat as currently described.

Pass percentage = 42.16
1C percentage = 11.48
1D percentage = 12.98
1H percentage = 11.22
1S percentage = 2.75
1NT percentage = 4.44
2C percentage = 2.39
2D percentage = 4.83
2H percentage = 5.78
2S percentage = 1.96
Total percentage = 100.00

Having done that, I then looked at the effect of shading the opening requirements for all bids by 1 fpc (i.e. playing a 14+ “Strong” 1C and a 9.0 to 13.8 fpc intermediate range.  The figures change to those below

Pass = 34.03%
1C = 16.79%
1D = 14.52%
1H = 12.39%
1S = 3.05%
1NT = 5.33%
2C = 2.62%
2D = 4.33%
2H = 5.16%
2S = 1.78%
Total = 100.00%

I actually prefer this balance, so for those jurisdictions which allow it, for anyone fancying playing DIP, I recommend switching to to the above ranges.  Dropping a further point down (a 13+ “Strong” 1C) makes too many hands open 1C, in my opinion, so I wouldn’t recommend it.  If you do switch to a 14+ 1C base, I would also suggest upping your 3rd/4th seat openings by 1 fpc, i.e. an 18+ 1C base.  You can probably follow the logic of this if you think about it a bit.

I also checked the other way:  adding 1 fpc to all the openings and making a 16+ 1C base.  I am aware of jurisdictions who won’t allow a 15+ 1C. It produces the following figures

Pass = 50.82%
1C = 7.41%
1D = 11.06%
1H = 9.44%
1S = 2.27%
1NT = 3.65%
2C = 1.98%
2D = 5.16%
2H = 6.11%
2S = 2.09%
Total = 100.00%

It’s not aggressive enough for my liking:  too many hands passing, and even the ones that open are not very obstructive.  I’m sure the method would function fine, but I wouldn’t play this range if I didn’t have to.  Also, if you do go to a 16+ 1C, don’t change the strong and intermediate ranges in 3rd/4th seat.  Same logic as above.

Regards, DipBridge

DIP: Weak Range Opening Bids

Continuing my diversion from fleshing out the 1NT opening responses, it seems a good time now to begin to describe the weak range openings.  One of the reasons I feel able to do this now is that I am able to conduct some useful simulations using Andrews’ deal software to see the potential effectiveness.  However, for the 1st and 2nd seat weak range openings, my ideas haven’t altered for some time.

The 1st/2nd seat 2S opening is the simplest.  It is a sort of weak two, 6.0 to 9.8 fpc, except

• It guarantees exactly 5 spades
• It guarantees at least 2 cards in the other three suits
• It cannot contain 4 hearts

The above conditions should ensure the obvious

• Spade fit can be accurately gauged
• 4-4 heart fits shouldn’t be missed
• Escaping from when in trouble is relatively easy (except, of course, with 1444)

The 1st/2nd seat 2D and 2H openings are inspired by a (May 2005 I think) Bridge World article by Doug Bennion.  Some 20 years ago, in pairs, I played a somewhat similar method (2D = any 3-suiter, including 5431’s) but this was before assumed-fit theory had even been thought of.  Here is a link to where you can find a copy of that original article now

http://www.bridgebuff.com/jammer.html

Once you have read this article, you will know what I mean when I say that

• 2D::  Long pointed, short round, Jammer, 6.0 to 9.8 fpc
• 2H::  Long round, short pointed, Jammer, 6.0 to 9.8 fpc

An additional constraint for each of the above is that they show at least four cards in the guaranteed major.  This (with the fairly tight range) ensures the openings serve a constructive as well as pre-emptive purpose.  There are some other subtle differences (for example 5530’s are allowed in DIP’s version).  So, to clarify the shape possibilities above

• 2D:: 4-5S, 3-5D, 3-5H & 0-2C OR 4-5S, 3-5D, 3-5C & 0-2H
• 2H:: 4-5H, 3-5C, 3-5S & 0-2D OR 4-5H, 3-5C, 3-5D & 0-2S

In a recent blog, I mused that the 3rd seat openings may remain the same as the 1st/2nd seat ones (we have discussed the 4th seat ones previously).  I have changed my mind on this – possibly aided by the ability to run some simulations.  In 3rd seat, then

• 2D::  Long diamond Jammer, 0.0 to 10.8 fpc:  Note:  3+, not 4+ diamonds, guaranteed
• 2H::  “Weak Two” H, 0.0 to 10.8 fpc:  shapes similar to 1st/2nd seat 2S except 6H322’s also allowed
• 2S::  “Weak Two” S, 0.0 to 10.8 fpc:  shapes as per 1st/2nd seat 2S except 6S322’s also allowed and the prohibition against exactly 5422 removed
  

As you can see, we are playing somewhat faster and looser in 3rd seat now, but some key structural integrity points remain

• Escaping from the Weak Two’s, if in trouble, needs to be supported, so the 2+ cards in side-suits rule needs to remain, and
• The 2D opening guarantees 3+ diamonds.  This is important IMO – I don’t like giving the opponents two shots when I am showing a weak hand type.  Having 2D showing D “length” prevents this.

I hope to update the system front page shortly.

Regards, DipBridge

DIP: 3rd & 4th Seat Opening Bids

While I prevaricate for a time on valuation methods and stronger responses to the 1NT opening, it seems an ideal opportunity to discuss and outline 3rd and 4th seat strong and intermediate range openings.

In DIP, 4 card major suits openings are emphasised in 1st and 2nd seat.  The as yet undiscussed weak range 2D and 2H openings also emphasise 4 card majors as well.  So, once you get around to opening in 3rd and 4th seat, it is assumed that many possible 4-4 fits with moderate strength or better between the two hands have already been discounted.  Remember, there are some balanced hands in the 10.0 to 11.8 fpc range which will have been passed, but if they contain a major, they can only be 4M333.

The number of hands which would naturally need to relay after an intermediate range opening has also effectively been reduced to nil.  As such, the benefits of transfer style openings in the majors has also largely been lost.  Further, because partner would have opened the majority of 10.0+ fpc count hands, there is little reason to stretch to open.  So somewhat antithetically to normal methods, DIP practitioners should go more conservative in 3rd/4th seat intermediate range openings than “normal” bidders.

With respect to the strong range, there are not too many hands which could easily FG relay opposite a 15.0+ fpc opening.  Whilst there are quite a few semi-POS possibles, there are fewer competitive advantages to be gained from a semi-POS structure, with at least one opponent and possible both already having been silent.  This suggests a possible switch to a more classic 1D ART & NEG, 1H+ FG POS relay structure, opposite a slightly stronger 1C opening (to bring more of responders potential hands into the FG POS picture).

Where does all the above lead to?  A 17.0+ fpc strong 1C opening and mostly natural 11.0 to 16.8 fpc intermediate strength openings.  Also, it is not incumbent to open 11.0 to 12.8 fpc hands if you don’t like the feel of them (which would likely mean in practice not opening if forced to show a bad suit, or to open 1D if you don’t have many of them, 4405 being the worst case scenario).

With 13.0+ fpc, you should always open.  Remember, the “best” hand that partner can come up with after having passed is an 11.8 fpc 5m4m22, so you shouldn’t miss a game if you pass a “bad” 12.8 fpc or worse in 3rd or 4th seat.

Speaking of “bad”, Thomas Andrews describes the ranges between points as follows

• 12.2 fpc::  “a good 12 count”
• 12.4 fpc::  “a very good 12 count”
• 12.6 fpc::  “a very bad 13 count”
• 12.8 fpc:: “a bad 13 count”

This seems a not unreasonable explanation method to adopt, when needed.

There are a few other residual points to consider for the intermediate range openings.  The first is the 1NT opening.  11.0 to 16.8 is clearly too wide a range for this.  As such, BAL hands are split into two ranges:

• 11.0 to 13.8 fpc
• 14.0 to 16.8 fpc

For 3rd and 4th seat openings, one of these BAL hand ranges is opened 1NT and one is slotted into the now slightly catch-all 1D opening.  There are two conflicting theories as to how one might allocate the above.

1. If the opponents are known to be going to compete, it would be better to have the stronger range in 1D:  then partner with diamonds can act, realistically hoping for one of (i) genuine diamonds, or (ii) a strong(ish) hand. However
2. If the opponents might double you for penalties, it would be desirable to have 1NT containing the stronger range:  this reduces the chance of getting in serious trouble.

As is often the case, the solution is a compromise, though a fairly optimal one I believe.  In 3rd seat (when the 4th hand opponent might still be very strong) 1NT gets the 14.0 to 16.8 range and 1D defaults to the 11.0 to 13.8 range.  In 4th seat, when both opponents are known not to be very strong, we try to capture the auction, with 1NT instead getting the 11.0 to 13.8 fpc range.  We put the stronger range into the 1D opening, to get the potential advantages if the opponents compete as discussed above.

Another residual point to consider is what to do with 4D5C hands.  In 1st and 2nd seat, these are put into the 2C opening.  Many other MOSCITO-like relayers would put these in with 1S(=D) but I think that cripples the 1S opening in competition:  4+ diamonds with a median of 6 diamonds is too great a range to handle.  By doing what DIP does, the minor suit showing openings average about 5.8 cards in the shown suit, which I think is quite workable.  However, with the ability to open 1D “sort of” showing diamonds in 3rd/4th seat, I think the balance changes considerably.  So, in 3rd and 4th seat, DIP opens 5C4D hands that are unsuitable for 1NT with 1D.  Consequently, 2C guarantees 6+ clubs, which is of course another good thing in competition.

The final residual point to consider is what to do with the two level pre-empts in 4th seat.  The answer is somewhat like most systems:  don’t have them.  The question is, what to use them for, or more accurately, how to use them to better define other bids.  The current proposition is to use 2D, 2H and 2S to show 14.0 to 16.8 fpc hands with good suits (probably KQxxxx or better).  This means that a same suit rebid of 2D, 2H or 2S either is minimum or doesn’t contain a good suit.  This should stop responder pushing too hard.  As always, there is a conflicting alternative:  play them as minimums, somewhat like Strong WK 2’s (for competitive reasons).  However, in 4th seat, the constructive use is preferred, so strong with good suit it is!

There is a case for making 2D, 2H and 2S similarly constructive in 3rd seat.  However, there is a competing case for maintaining pre-emptive weaponry in 3rd seat as well and currently, that case is deemed more compelling.

Please read the front page which contains the system for the net effect of all the above.  I’ll updating it fairly soon.

Regards, DipBridge.

DIP: Basic Hand Valuation

I’ve been distracted tangentially recently.

It started because I was thinking about the 1NT response structure:  in particular the invitational sequences.  This got me thinking again about hand valuation.  If it’s applicable in its basic form anywhere, it’s for auctions like 1NT 2NT and 1NT 3NT (or their DIP equivalents).  This led me (back) to the work of Thomas Andrews.  SD assured me his work was significant, and indeed it is.  You can find it, or get to it, from here

http://bridge.thomasoandrews.com/mozilla.html

It is his hand evaluation work that is of most interest.  As you know, DIP currently uses ppc (Practical Point Count) valuation, where A=4.5, K=3, Q=1.75 and J=0.75.  It would also be reasonable to name this valuation method “Fourths” (you will see why later, apart from the obvious point that it uses a quarter point granularity of sorts).

Though Andrews cautions with the risks of using his current conclusions (and some of his work is ongoing), I am sufficiently impressed to move DIP across to it now.  Specifically, DIP will adopt his “Fifths” evaluator, where

• A=4.0
• K=2.8
• Q=1.8
• J=1.0
• T=0.4

In DIP, we’ll refer to it as fpc (Fifths Point Count).  Like ppc, it shares a 40 point deck with the classic hcp count, which should make conversions and explanations relatively easy when needed.  Also, I have always found it annoyingly difficult to write 1/4, 1/2 or 3/4 in DIP, so am looking forward to being able to simply write “0.8″ or similar where needed.

In time, it may well be that I need to change some of the opening and response ranges to cater for the use of fpc.  We’ll keep them roughly as they currently are, for the present, and cross that bridge when we come to it (that is, after more experience with the method).

I think it is fair to compliment Woolsey as to how close his intuitive thoughts were to Andrews calculated ones, except for the apparent under-weighting of the J.  Scaling “Fifths” to where A=4.5, we see how close Woolsey was (ppc first, then fpc scaled in brackets) …

• A = 4.5 (4.5)
• K = 3 (3.15)
• Q = 1.75 (2.025)
• J = 0.75 (1.125)
• T = n/a (0.45)

Interestingly, Andrews also refers to Martelli’s valuation method (named BUM-RAP) which is geared to suit contracts.  It differs from ppc only in that Q=1.5 and T=0.25.  Nevetheless, I expect with many suit-contract auctions, users of DIP will be going down a different route than simplistic hand-evaluation, so this direction of thinking is not of great short term relevance.

I think I’ll use the change in valuation from ppc to fpc to change this blog’s structure slightly.  I’ll pin the current system, only as far as discussed in the blog, to the front page (and maybe begin a change log).  I’ll then let the current front page go to its “natural” place at the bottom.

Until then!

Regards, DipBridge