Round 2, Board 13

[inquiry]

[hv=d=n&v=a&n=s764h94dakq863ca9&s=skj2ha5dt952cjt82]133|200|Scoring: IMP

Opponents do not bid.

 

[/hv]

 

 

3D=10, 4D=7, 1N=5, 3N/5D=2

 

 

3DN gnasher/catch22

3DN hrothgar/Free

3DN karlson/threenobob

2DN sallyally/joylson

1NS ant590 - crayzeejim

1NS bluecalm/redds

1NS elianna/awm

1NS jlall/hanp

1NS kristen33/jillybean

1NS peachy/lg62

1NS rogerClee/cherdano

1NS Siegmund/MSchmahl

3NTS East4Evil/sohcahtoa

3NN Flycycle/Wackojack

3NN jdonn/gib

3NS kfay/jchiu

5DN lobowolf/bkjswan

3NS mbodell - javabean

3NS olegru - driver733

3NS tlgoodwin/timg

3NS tylere / bid_em_up

[bluecalm]

I am not convinced at all that 3♦ > 1NT let alone difference that big.

I was sure we are in top spot after the bidding and seeing partner's hand.

Why exactly 3♦ scores so heavily here ?

[bid_em_up]

I will object to the scoring of this board. Since double dummy defense will always find the right lead (a heart), of course, 3N will score poorly. In real life, a spade lead will give yield a 9th trick immediately, and a non-heart lead gives 3N plenty of chances, 3N will make frequently (imo). On a non-revealing auction such as, 1D-1N-3N, the chances of either major suit being led are fairly equal (again, imo).

[hrothgar]

For Free and I, this was one of the more interesting hands.

 

North opened 1♠, showing an unbalanced hand with 4+ Diamonds

 

South answered 3♣ (pass or correct)

 

North corrected to 3♦ and there we sat.

 

I was expecting a nice score because we were able to shut out the heart suit. I was somewhat surprised that the schizophrenic opponents were unwilling to enter into this auction, particularly given some of their other overcalls. (Like that red 2♠ call over a strong NT opening)

 

(FWIW, I think that 1NT deserves a better score)

[awm]

I agree with bluecalm here. Against 3♦ the opponents will often take two spades, a heart, and a club. Certainly there exist some positions where you can get ten tricks (like both spade honors onside) but I think this is against the odds. There are also positions where 3♦ fails (almost any time ♠AQ are both offside).

 

On the other hand, 1NT has eight cold tricks on top. And there are nine tricks on a spade lead, and play for nine tricks on a club lead. There's even enough discarding pressure on the running diamonds that you could conceivably make nine tricks on a heart lead!

[JLOGIC]

Yeah strongly disagree with the scoring here, agree with awm.

[rogerclee]

Also strongly disagree with the scoring, 3D= and 1N+1 (or more) seem extremely common.

 

3N and 5D don't deserve the same score, 5D is down probably 2 and 3N is down only 1 or making on a bad lead.

[jdonn]

Save me objectors!

[cherdanno]

Ben you really can't score this one based on double-dummy analysis. To make 10 tricks you need either both spade honors onside, or you need to

- first guess the clubs (assuming there is a way to establish a club trick), to develop a spade pitch, and then

- have one spade honor onside and guess correctly which one.

 

That's a lot of guessing that your double-dummy simulator did for you there.

(Btw, even double dummy my quick simulation showed 3D making 10+ tricks only 60% of the time, so I really don't know where you got the big difference between 3D and 1N from.)

[awm]

Agree with Cherdano.

 

Double dummy will always lead ♥ vs 1nt (any other lead gives good play for 150) and will always work out whether to play on clubs or spades in 3♦ (maximizing odds of 130). This gives a massive advantage to 3♦; 1nt is better single dummy.

[Free]

For Free and I, this was one of the more interesting hands.

 

North opened 1♠, showing an unbalanced hand with 4+ Diamonds

 

South answered 3♣ (pass or correct)

 

North corrected to 3♦ and there we sat.

 

I was expecting a nice score because we were able to shut out the heart suit. I was somewhat surprised that the schizophrenic opponents were unwilling to enter into this auction, particularly given some of their other overcalls. (Like that red 2♠ call over a strong NT opening)

 

(FWIW, I think that 1NT deserves a better score)

I wasn't happy with the auction because I had a solid suit and need only 2 tricks in your hand. But afterwards I was glad we were lucky on this one ;)

[JLOGIC]

Yeah the combined chances of a spade lead for 150 in 1N, and the strong chance of only getting 110 in 3D (I estimate that at much >50 % irl) make 1N better.

 

Also 4D is ranked way too high for the same reason.

[jdonn]

Agree with the point that 3NT should outrank 5♦ since 3NT won't be down more than 1 but 5♦ will often be down 2.

[inquiry]

nonsense deleted, see comments below for hint as to why

[matmat]

As for contracts, 1NT is the limit on a heart lead, on a spade lead, you will make 2NT, not 3NT.

Hi,

am I missing something?

 

seems in a NT contract you're always getting six diamonds and two round aces?

[inquiry]

As for contracts, 1NT is the limit on a heart lead, on a spade lead, you will make 2NT, not 3NT.

Hi,

am I missing something?

 

seems in a NT contract you're always getting six diamonds and two round aces?

Whoops.. you are right.. I will have to do some serious corrections. I only ran simulations on diamonds when i redid it.. and I miss remembered the stuff...

[hanp]

somehow this landed in the wrong thread.

[inquiry]

Opponents have 9 hearts and only 7 Spades, Opponents suits are:

 

KQJT87xxx for hearts

AQT98xx for spades

 

In my simple-mindedness, it seems more likely they would have longer hearts to lead and better (safer) holding to lead from (sequence) with hearts than spades.

 

As for contracts, 2NT is the limit on a heart lead, on a spade lead, you will make 3NT.

 

As for diamond contract, 3D is 100% and 4D makes in the 80% range (double dummy). So what we have is 3NT is often down one, but might make. 5D is always down one but might be down two. So 3NT has to score better than 5D.

 

1NT usually scores 8 tricks (120) but might score 9 (150); 3D usually scores 4 (130) but might score 9 (110).

 

So I see the complaints on this hand. I still think heart lead is more likely than a spade lead. I did a small group of similations where I looked at what major would be lead (major 100% of time for this). I based this on lead the longest major, or if tied, lead the major with safest sequence, or from "strongest" major card holding. In this short test, hearts was the longest half the time, and had a leadable sequence or was the strongest when tied (3-3, 4-4) the majority of the time there was a tie, the final count being heart would be lead 70% of the time (a few were subjective). So it will make 30% or so under these situations.

 

Clearly 3NT should score better than 5D (at worse it ties it, and it can beat it two ways.. 3NT will make on spade lead, and is never down more than one, while 5D will not make and is possibly down two). So 2MP for both is clearly wrong.

 

The problem is what part-score should score the best? I hate to have to admit it, but once again I reverted to matchpoint scoring this thing based upon "percentages" and what the field in the competition bid, then converted it back to a 12 point scale.

 

5D dropped to 0, and everyone got a point for not bidding that, then for:

3D (1/2 pts for each in diamond, plus (0.82-0.3) times the number of people in NT)

1N (1/2 pt for each in 1 Nt, plus 0.3 times number in diamonds)

3N (1/2 pt for each in 3NT, plus 0.3 times those in both 1NT and diamonds)

 

If I did this right, the anticipate mp were:

5D 0 ----------> round up on a 12 point scale to 0

3D 10.82------> round up on a 12 point scale to 7

3N 8.1 --------> round up on a 12 point scale to 5

1N 3.6 --------> round up on a 12 point scale to 4

 

For the "round up" I convert the Mp calculated on a 20 top score to a 12 top score and then increase to the nearest whole number.

[JLOGIC]

3N now scores higher than 1N?

 

It seems like your formula is off. You make 1N>3D only 30 % of the time. However, as far as I can tell, 1N is better than 3D the 30 % of the time it gets a spade lead, plus the 20 % of the time that 3D only makes 3.

 

So if my math is right, 1N>3D 44 % of the time.

 

Also, 1N should get a point 70 % of the time vs 3N, and 100 % of the time against 5D.

[hanp]

I think the method is good Ben, but you forgot to give those in 1NT points for those in 3NT going down.

[JLOGIC]

I have that 4 people were in 3D, 8 1N, 8 3N, 1 5D.

 

So 3D should get: (.56*8)+(.7*8)+(.5*3)+1=12.58

 

1N should get (.5*7)+(.7*8)+(.44*4)+1=11.86

 

3N should get (.3*4)+(.3*8)+(.5*7)+1=8.1

 

5D should get 0

 

Converted to a 12 point scale that is:

 

3D=7.55

1N=7.12

3N=4.86

 

With rounding that is:

 

3D=8

1N=7

3N=5

 

The 2 errors i found with your method were 1N was not getting .7 vs 3N, and 1N was only getting .3 vs 1N when it should get ,.44 (it wins the 30 % of the time 1N makes 3, and wins the 20 % of the time 3D makes 3).

[inquiry]

3N now scores higher than 1N?

 

It seems like your formula is off. You make 1N>3D only 30 % of the time. However, as far as I can tell, 1N is better than 3D the 30 % of the time it gets a spade lead, plus the 20 % of the time that 3D only makes 3.

 

So if my math is right, 1N>3D 44 % of the time.

 

Also, 1N should get a point 70 % of the time vs 3N, and 100 % of the time against 5D.

This surpised me too, but I didn't double check it. It turns out that I left off the scores for 1NT beating 3NT when 2NT is the limit

 

For 1NT, it gets 1/2 point for all other 1NT's, there were 8 in all, so that is 3.5 matchpoints. It gets 1 point for the 5D contract, that is 4.5. It gets 30% of a full point for each 3D/2D contract when it makes 3 (.3x4 = 1,2), plus it gets .18% of a full point for each diamond contract where 3D is the limit, but correcting for when 9 tricks make because that has already been factored in, so it will be 70% of .18x4 or 0.504 pts. In addition, it beats 3NT 70% of the time, so .7*8 = 5.6. Totally those up you get 3.5+1+1.2+0.5+5.6 = 11.8.

 

11.8/20 is 0.59 and 59% of 12 is seven.

 

So on this hand, both 1NT and 3D will get a SEVEN now. Up until someone shows another major flaw.

 

I will post a corrected score and list of who is where now

[awm]

I do not understand your "4♦ makes in the 80% range."

 

If the ♠AQ are both behind the KJx, then a spade lead sets 4♦ off the top. That by itself seems to reduce 4♦ below the 80% range, even double-dummy.

 

Suppose a heart lead against 4♦. If both spade honors are onside then you can obviously make. Otherwise you need to establish a club trick. So you pull trumps and lose a club trick. Now opponents cash a heart and a spade is lead through dummy. You have to guess which spade honor is onside, and if you go wrong you'll be down.

 

In practice, I'd say that 4♦:

 

(1) Always goes down if ♠AQ are both offside (25%)

(2) Makes if both ♠AQ are onside, assuming we play for that (25%)

(3) When one spade honor is onside (50%), makes if we can establish a club trick (75%) and we guess which spade honor is onside (roughly 50% of the time).

 

Adding these up I get around 25% + (50% * 50% * 75%) < 44% for 4♦ making. Perhaps we can add a little because our spade guessing ability is better than 50%, and add a little because the opening lead might be a club. But I also assumed that we can always decide correctly which of ♠AQ on or ♣ trick to play for, which might not be true at the table either.

 

I just can't fathom 4♦ being remotely close to 80% at the table (more like 50% or a bit below). Your double-dummy simulator is overestimating the odds of 4♦ making by almost a factor of two by assuming that we always get the guess right on the spade suit.

[Mbodell]

FWIW I'm in the process of single dummy simulating this using Jack. My early too small sample size suggests that this still grossly underestimates the chances of 9 tricks in nt and overestimates the chances of 10 tricks in diamonds. It will take quite a while though as single dummy is super slow, so I might not update results until Monday.

[gnasher]

I'm a bit puzzled by all this talk of nine tricks in notrumps. If the bidding starts

  1♦ pass 1NT pass

It seems to me overwhelmingly likely that West will lead a heart.

 

The possible explanations for East's failure to overcall are:

- He doesn't have five hearts. Then West has five hearts, and will lead them 100% of the time.

- East has five hearts but a poor hand. However, that would usually give West a takeout double of 1NT, so can almost be ruled out by the bidding.

- East has five poor hearts in a moderate hand. That will probably make a heart lead automatic from the West hand. What would you lead after this start from AQxx KJ9x xx xxx?

 

(Edited to (1) correct my confusion about East and West, and (2) make the example more believable.)

Edited August 30, 2010 by gnasher