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: Responding to 1NT [II]

Since writing part [I] of this section, the signifcant other developer has been in touch about it.  I’m going to get sick of writing that term (significant other developer) after a while, so let’s refer to him here on as SD (which is preferable to the obvious alternative).

SD had some good ideas and thoughtful opinions as always.  I’m going to order them in this blog to suit my subsequent purposes, rather than how he sent them to me.  This is because they are somewhat intertwined (though not for reasons that are immediately apparent).  A summary of his ideas, opinions and thoughts is

• Why not switch the proposed treatment for 4H4S INV hands (currently 1NT 2D 2H 2S) with that for 5H INV hands (currently 1NT 2C 2D 2NT)?  SD’s main rationale was so that after 1NT 2D 2H 2S 2NT, responder could then bid 3m with 5m (or concentrated 4m maybe).
• If STAY(man) is to be used over 1NT (and more importantly, 2H to be available as R over 2D showing no M) why not allow 5m4m22 hands into 1NT?  There is sufficient space to do so (but not over 1NT 2S R as I had planned to use some time ago, but discarded).
• Given that if opener has a major he’s 4333, there is minimal concealment advantage when opener is declarer (which SD understands was behind the Scanian rationale for transferring with 4M’s).  So why not reverse the STAY responses, so 2H shows 4=3=3=3 and 2S shows 3=4=3=3?
• Should opener always super-accept a transfer with 4333 shape?  SD thinks maybe not.

SD also had some other comments (puppet-based alternatives, really) which are not directly relevant to what will appear below and won’t appear in this blog.

OK, let me re-state (and mildly re-order) the invitational hand types that we would like to find a home for below their “safety level”.

1. BAL, no M
2. 4S not 4H
3. 4H not 4S
4. 4S & 4H
5. 5S
6. 5H
7. 5S & 4H
8. 4S & 5H
9. 5S & 5H
10. 5H, 4+m
11. 5S, 4+m
12. 5+D (possibly with 4M) or 6+D
13. 5+C (possibly with 4M) or 6+D

This list is expanded from the original, with items 1-8 being the ones under primary consideration.

To repeat, SD’s first idea above was to play 1NT 2D 2H 2S as 5H, INV (swapping the 4S4H hands to 1NT 2C 2D 2NT).  I wasn’t initially a fan – it broke the “2D = 4 or 6 H if INV” rule, for one thing.  So I ruled it out, but then thought about it some more.  The fact that the 1NT can have one major, but not both, gives some interesting properties to STAY-like sequences in DIP.  Doing what SD suggested to achieve the primary desired effect (expression of INV 5H/5m hands) had a powerful side-effect:  all of cases (1) to (4) above could be brought safely into STAY, not just case (4).  On further thought, so could case (7), 5S & 4H.  The reason these 5 cases can be handled by STAY is because all potential 4-4 M fits are cleared up on the first response to STAY.  The only thing left to resolve from cases 1,2,3,4,5 & 7 is whether there is a 5-3+ S fit (and even that is already clear after a 2H 3=4=3=3 or 2S 4=3=3=3 response). I (very much) hope my logic above is sound, otherwise the whole house of cards below will fall apart.  Let’s cross fingers and assume it is.

So, by adopting SD’s suggested change, we have freed up at least four sequences that are safety-level relevant (1NT 2D 2H 2S, 1NT 2D 2H 2NT and 1NT 2H 2S 2NT and 1NT 2S) and only have two cases from the original 2C response that need alternative handling:  (6) 5H, for which we have already allocated a home, and (8) 5H & 4S, which we’ll give to the 1NT 2D 2H 2NT sequence.

So, the sequences 1NT 2H 2S 2NT and 1NT 2S are now freed up.  So what to do with them?  Let’s move to SD’s second suggestion (desire?):  allowing 5m4m22 hands into the 1NT opening.  Always a nice aspiration, my traditional fear has been the damage done to the safety-level of case (9) hands, those with 5S & 5H.  But now, we have an elegant way to deal with them:  1NT 2H 2S 2NT (NF).  I quite like the feel of this, as it is sort of analagous with 1NT 2D 2H 2NT showing H/S hand as described earlier.  So

• DIP can now officially allow 5m4m22 hands into the 1NT opening (with a decision still to be made as to whether to prohibit them from the 1S and 2C openings, with my inclination being “yes”), and
• 1NT 2S can be put to a more specific use.  This is likely to be both minors, of all strength ranges, a variant of what had been planned for it anyway.
• We’ve catered explicitly for cases (1) to (9) above, and cases (10) & (11) can be implicitly handled by responders 3rd round bidding of 3m after one of the three possible 1NT 2X 2Y 2S 2NT auctions

Assuming no logical flaw, we’re looking pretty good.  Case (12) and (13) can and should also be handled via STAY and simply rebidding 3m over the relevant response.  This gets a chance to find the 4-4 M fit on the way through, if relevant.  Finally, over a 2M response to STAY, 3M is INV, 3OM is R.  Note that in 1NT 2C 2S 3S, responder might have 4 or 5 S (if he chooses not to revalue the latter upwards).

So, the overall response structure to 1NT (though not complete) now looks like

• 2C:  STAY (ART FG R or 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)
• 2S:  both minors, any strength

SD’s third suggestion was to possibly reverse the M responses to STAY.  The short answer is that I don’t think you can and still play the above structure.  There are too many handling issues (basically, not enough bids over 2S=H and too many over 2H=S).  You COULD make it work by also switching the 5S cases with 5H ones wherever they occur, but playing 1NT 2D 2H 2S as showing 5S and not promising H is a bit too rich for me!

The final thought from SD was the merit of forcing a “super-accept” with a 4M333 when there is a 4 card fit to suit shown by TRF.  There is certainly now no compelling requirement to do so (with all the 4M invites moved into STAY) but it still feels right to me.

The above structure now feels right and sits comfortably within the system.  The downside would appear to be a fair bit of work on the 1NT 2C sequence which might be difficult to unscramble if 4th hand competes.  Nevertheless, the fact all WK sequences have been removed gives some latitude in this respect.  There is an argument for playing pass as forcing over some interference to 1NT 2C sequences (maybe at the two and four level)?  This blog is already long enough, so we’ll leave that for another time.

Regards, DipBridge

DIP: Responses to 1NT [I]

Back again.  This post would have been sooner except the responses structure to 1NT (BAL no M, or 4M333) have not been finalised.  Unfortunately, they still haven’t been finalised, but at least the thinking behind the requisite structure is becoming clearer.  As such, I am in a position to partially outline a potential structure.

The decision to include 4M333 hands as well (they now comprise 2 shapes of the 12 possible in the opening) was a fairly late one.  It is amazing how much the possible presence of a major suit complicates the response structure.  Nevertheless, here are some thoughts.

The “safety level” for invitational hands that are not 5+/5+ or 6+ in shape is usually 2NT.  I am going to assume for the present that inviting with invitational hands is regarded as desirable (there is a case for simply forcing to game with such hands, allowing extra space for strain investigation as needed).  If so, one needs to cater for the following invitational hand types at or below 2NT

1. BAL, no M
2. BAL, 4H
3. BAL, 4S
4. BAL, 4H & 4S
5. BAL, 5H
6. BAL, 5S
7. BAL, 5H & 4S
8. BAL, 4H & 5S

I’ve been through quite a few permutations as to how these might be handled.  Originally, I was proposing 2C as a puppet to 2D.  Or more accurately, I was thinking about a structure where each of these 8 types was somehow shown explicitly.  I just couldn’t get it to work* (maybe someone can supply a mathematical proof to show that I couldn’t)!

In a related, but different conversation, I had suggested to the significant other developer that maybe Stayman and Transfers had “had their day” as they were unlikely to have naturally evolved in an optimal form by accident.  Well, that may be true, but I find myself somewhat eating my words with what I’m about to suggest.  I think 2C as STAY(man) is probably going to work best here, but with one slightly unusual caveat:  that if invitational, at least one 5M is promised.  The reason will become apparent.  The responses to STAY are fairly normal (though by definition, more narrow)

• 2D:  no M
• 2H:  3=4=3=3
• 2S:  4=3=3=3 (it is possible that a subsequent version will have 2S:  4=3=3=3 MIN and 2NT:  4=3=3=3 MAX, but until the rest of the structure is complete, it is not yet clear)

Over these responses (and 2D in particular) 2S will show 5S INV and 2NT will show 5H INV.  It should be clear from these continuations and the fact that STAY has already accounted for any 4-4 M fits, that cases 5-8 above can be satisfactorily handled by this method.

The STAY path will also be used by strong hands that wish to R.  I had originally toyed with a direct 2S over 1NT fulfilling this functionality (better when 4th hand intervenes) but

• I need the direct 2S now for something else, and
• The extra step gained by using an indirect 2H rather than a direct 2S as R is quite significant when it gets to control showing.

So, over the 2H 3=4=4=4 and 2S 4=3=3=3, at least one three level bid (yet to be determined) will need to be reserved as control asking R.  Over 2D (no M) then 2H R, the structure will continue

• 2S:  1/S clubs (resolves as for 3C+ below after 2NT R)
• 2NT:  4C & 4D
• 3C:  3=3=4=3
• 3D:  2=3=5=3
• 3H:  3=2=5=3
• 3S:  3=3=5=2, B+2 or greater QP’s (9+ QP’s, i.e. A=3, K=2, Q=1)
• 3NT:  3=3=5=2, Base or B+1 QP’s (i.e. 7 or 8 QP’s, rarely 6, which is counted as “Base”)

You are getting a bit of a taste of the underlying relay structure above

• Low length first
• High shortage first
• Base = MIN(ppc) * 6 / 10, rounded down to the nearest integer (12 * 6 / 10 = 7.2 = 7 in the above case).  Note also that the use of ppc rather than hcp protects a little against B-1 QP hands being in range for the various openings.
• When two steps are available to run on and show QP controls (3S & 3NT), 3NT shows B or B+1, 3S shows the rest (although in some circumstances, 4C+ or 4D+ can be used to show B+4 or better)
• When three or more steps are so available, all steps but the first show B, then B+1 etc.  The first step then shows the rest (see the 4C & 4D example immediately below)

The both minors hands above show controls slightly differently (as they have an extra step).  After 3C R

• 3D:  2=3=4=4
• 3H:  3=2=4=4, B+2 or greater QP’s
• 3S:  3=2=4=4, Base QP’s
• 3NT:  3=2=4=4, B+1 QP’s

I’ll expand more on the resolution and control showing at a later time.  Suffice to say, it is not absolutely optimal and not intended to be.  It is intended to be practical, easy to remember, and nearly optimal.

OK, cases 5-8 from the original list are handled by STAY.  What about cases 1-4?

We handle 3 of the 4 cases by using the transfer mechanism provided by 2D(=H) and 2H(=S).  It is worth noting that if INV strength, these will have a 4M and/or a 6M, but not a 5M.  The relevant sequences are

• 1NT 2D 2H 2S (4H & 4S, INV)
• 1NT 2D 2H 2NT (4H, INV)
• 1NT 2H 2S 2NT (4S, INV)

That deals with cases 2-4.  It is almost certain that opener will be required to super-accept with 4 trumps opposite a transfer.  After this, there is not likely to be re-transfers thereafter (except, maybe, in strong auctions) as there is little advantage to opener being declarer when known to be 4333 shape.

The remaining case, is handled by what is initially a range-asking 2S.  It is almost certain that if showing a MAX, opener will be required to give a minor suit preference, so after 1NT 2S

• 2NT:  MIN
• 3C:  MAX, C >= D
• 3D:  MAX, D> C

I hope you can see where all the above is heading.  I hope I can (sensibly) complete it.

Regards, DipBridge

* remembering that I also needed to have a sensible sequence to allow simple FG relaying