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Author Topic: system versus optimism.  (Read 2324 times)

kenberg

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system versus optimism.
« on: November 18, 2020, 03:14:18 PM »
This hand came up (I was North) in an acbl matchpoint game. We were in 6 !H making 7 which surprisingly scored 66%. I had the bots give it a try and they reached 7 !H with no trouble. But we could vary the hands some and then maybe 6 !H is high enough.

    !S void
    !H AQJ76
    !D 873
    !C AK973



    !S A43
    !H KT4
    !D AKQT9
    !C 85

North deals and opens 1 !H, everyone is vul.  Our convention agreements were limited but we easily reached 6 !H, but not 7 !H, certainly not 7 NT.  The acbl game is reasonable enough, meaning that if you mostly reach reasonable contracts and don't do anything grossly dumb in the  play then you can expect to finish with a decent score. But 7 !H would be nice here. The !H J could be useful if that suit breaks 4-1, and the !D T could be useful when E holds four !D to the J. And of course the !C K is a very nice card. Ten red tricks, three black ticks, that's 13.  But I could have the !C Q instead of the K, and then?

Anyway, here was the robot auction:


1 !H   2 !D
3 !C   3 !H
4 !C   5NT
7 !H

The 2 !D was natural and game forcing with 4+ in the suit. The 3 !C showed extras, so the self-alert said, and with 4+ cards. The 3 !H set trump, the 4 !C was self-alerted as a cue. But the 3 !C did not show the A, so the 4 !C apparently showed the ace. The K is still in question. We might think we have to worry that the 4 !C cue was on the K w/o the ace but apparently not. After all, the 3 !C showed extras. Anyway, then the 5NT was the grand slam force, asking for two of the three top honors, so N bid 7 !H.

Can we find a better sequence. By better I mean such that we stay out of 7 !H when the hands are

    !S Q
    !H AQJ76
    !D 87
    !C A9732



    !S A43
    !H KT4
    !D AKQT9
    !C 85

I'm not sure 7 !H is impossible, although I don't really see how to do it. I haven't tried the bots on this, maybe their auction would now start 1 !H - 2 !D - 2 !H. That seems pretty restrained to me.

I'm fine with accepting that there is often uncertainty both in bridge and in life, so we place out bets. But science can be useful, again that's both in bridge and in life.

Any thoughts?
« Last Edit: November 18, 2020, 03:18:52 PM by kenberg »
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Ken

wackojack

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Re: system versus optimism.
« Reply #1 on: November 18, 2020, 04:59:51 PM »
OK Here goes with a 1  !C system that my friend plays and I try to.
 !S -
 !H AQJ76
 !D 873
 !C AK973

 !S A43
 !H K104
 !D AKQ109
 !C 85

2 !H  (9-14) 5 !H +5 or 6m       2NT (asking bid)
3  !S (13-14  5  !C)                  4 !C (Asking for short suit)  {4 !D =  ! !D singleton; 4 !H =  !S singleton; 4  !S =  !D void; 4NT =  !S void}
4 NT ( !S void so 0535)            5  !C (asking about aces and Kings)  {Count A=2 K=1}Step 1 =0 or 3, step 2 = 1 or 4; step 3  = 2 or 5}
5  !H (A  !H AK  !D)                  5  !S (Q ask in long suits)  {step 1 = 0, step 2 = LR Q; step 3 = HRQ; step 4 = both Queens}
6  !D (Q !H) not Q !C                            ?

At this stage South knows that partner has  !S void;  !H AQ?xx;  !D ?xx;  !C AK??x = 13HCP.  So all the ??? could be spot cards.  So with 3-2 breaks in the red suits 13 top tricks can be counted.  Sadly there is no room for an asking bid to find out if partner has the J !H.  Needing 3-2 in both suits and without knowing partner has J !H, the criteria for a grand is not met so bid 6 !H.
         

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kenberg

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Re: system versus optimism.
« Reply #2 on: November 18, 2020, 10:54:06 PM »
Very interesting.
I just don't have the patience to learn the details of various artificial systems nut there are times when they produce results. No denying that.


Playing matchpoints there is probably an argument for bidding 7 !H once you learn partner is 0=5=3=3 with the !H AQ and the !C AK, especially if the bidding leaves open the possibility f him also having a red J.
The argument has its flaws: If we assume that everyone will be in at least 6 !H then all we need to do is to bid 7 if the chances are better than 50%. If hearts split 3-2, which they will do more often than not, then we can bring this in when the diamonds split and also when the diamonds are 4-1 with the length with E. Say there is a !C lead. Win it, play three rounds of trump ending in hand, cash the two high diamonds and see what happens. If W shows out you have a marked finesse.
I have not calculated it out but I think the odds are better than even to bring in 13 tricks.
But the flaw is assuming everyone gets to at least 6 !H. We got a pretty decent result just for being in 6 and we put that at risk by bidding 7.

So yes, probably we do not bid 7 even with the information that your system discloses.

Which probably means we don't bid 7 playing any system. If we do not bid 7 knowing all that we found out, could we really expect to find out more?

So 6 !H is looking like a nice sensible contract.
 
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Masse24

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Re: system versus optimism.
« Reply #3 on: November 19, 2020, 01:17:37 AM »
Interesting auction the bots had. One I would not have considered. But I sorta like it.  ;D


My auction:

1 !H  — 2 !Da       
3 !Cb — 3 !Hc   
3 !Sd — 3NTe
4 !Cf — 4NTg   
5NTh  — 6 !Ci
7 !Cj — 7 !Hk . . . (maybe even 7NT)

a) GF - though GIB and many others play this as 4+ (and I do too with most people), I am starting to play it as 5+.
b) Extras - I have always preferred that a high reverse shows extras. Roughly 15+.
c) !H are trump!
d) !S control
e) Serious 3NT
f) !C control
g) RKCB for !H
h) Two key cards and a void . . . which on this auction must be spades, inferentially giving North three diamonds.
i) Queen ask. Pretty standard that next step is queen ask, plus -- this is Kantar's method. Here, North knows South is groping for the grand since the auction is already at the 6-level.
j) Yes, trump Q plus the !C King.
k) Grand -- okey dokey. Almost pulled the trigger on 7NT.   

South can't legitimately--with confidence--pull the trigger on either 7!H or 7NT. Can he?

The decision to go to the 7-level, though, is really made when he asks for the trump Queen after partner shows two keys and a !S void. His 6 !C Queen ask gives partner permission to go to the 7-level. South has a close, difficult decision after partner's 5NT. The only clue he has is that North promised extras. He knows of partner's two aces at this point. He knows partner has nothing in the !D suit (except three cards). So where is the rest of partner's paint?

It's not a terrible gamble ---- at worst about 49+ percent? (Where is Ken when you need a math guy?)

Knowing of the 8-card !D fit, the Jack will drop any time the suit is 3-2 or 4-1 with the Jack stiff. 72.5% or so. But South also needs the !H suit to run. But not knowing of the !H Jack, all South knows is the 8-card fit with AKQ, which requires a 3-2 split (only 68%) to run.

Without a red Jack--which is what South is hoping North has at least one of--I calculate the 7-level contracts at between 49% and 50%.

With the !H Jack, 7NT is about 72.5% (Help me out, Ken!) --- the percentage of the !D suit running without the Jack. With the !D Jack (and not the !H Jack), the hearts must run, so 68%.

A worthwhile gamble--due to the possibility of North possessing a red jack--assuming everyone else bids the small slam?


ADDED: I created a Bridgewinners bidding poll with the South hand, using my auction above, with the moment of truth coming after partner's 5NT response to our RKCB ask. It is more or less a consensus to make a move toward the grand. Most people asking for the Queen with 6 !C.

So we're committed to playing in 7 of something if partner has the trump queen.

Whether those polled agreed with my auction to that point is unknown. 

« Last Edit: November 19, 2020, 09:13:02 PM by Masse24 »
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kenberg

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Re: system versus optimism.
« Reply #4 on: November 19, 2020, 01:45:22 PM »
The situation with hearts, as S looks at his KT4,  is a little better. than just hoping for a 3-2 split.  In addition to the J being stiff, there is the possibility of N holding AQ9xx and the Jxxx being with W. Or even N holding  AQ8xx, and E holding the stiff 9. That would be a bit lucky but the 4-1 split is unlucky so we hope for some karma.

I might work it all through. But it seems like picking up the hearts should be a pretty fair shot.

There are always unknowns, beyond the reach of a system.  As mentioned, I was surprised to find we scored 66% for 6 !H making 7. It's pretty much impossible to go down so the explanation must be that about one-third of the players settled for game. And that means that if the hands were a little different, so that 7 !H is more iffy,  then I might decide that probably few will be in 7 (that was true) so I must decide whether to try for 100% while risking 0% or simply settle for 66%.   i want better than even odds for that bet. But still, a third of the field settling for game? I don't get it.

The robots play that in the auction 1 !H - 2 !D - 3 !C, the 3 !C  shows extras. In my early days of duplicate I heard a Steve Robinson lecture. Steve commented that whatever system you might be playing, 1 !H - 2 !D - 3 !C shows extra values. Seems that should get most pairs to at least 6 !H. But it didn't.
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