[kgr]

Scoring: IMP

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Your partner opens 1NT: 15-17, standard without 5cMajor, but can sometimes have a singleton, a 5c Major, a 6c Minor...
You options are (some kind of Beeman):
1) 2♦ transfer to ♥. Partner will bid:
   a ) 3♥ with a 4c♥ (not 4333) and min or
   b ) 2NT with a 4c♥ (not 4333) and max
2) bid 3♦: limit with an unknown 6c Major. Partner will bid:
   a ) 3♥ if he is minimum for ♥
   b ) something else if not minimum for ♥ (3♠:good ♥, bad ♠ / 4♣: bid your suit in transfer / 4♦: bid you suit).
...How do you start and when do you continue to Game? ...and how close is (what other options you considered)?

[Jlall]

I would invite game (3D in your system).

[dellache]

I would bid 2♦ with no second thoughts, this is real garbage, with a lot of losers. I very much doubt the game will in average be more than 50% when pard accepts. Even 4 aces is not enough in itself to play a good game NV.

The problem with 3♦ is that you also will play a 50% 3♥ partial when he rejects the invitation, when you could play safely in 2♥. When that happens you also lose 4IMPs (so lose 2 Imps in average). So your "investment" in trying for game must be compensated by playing a game ABOVE 50% when he accepts. The question which arises is : will your LHO balance 2♥ ? I don't think so. So let's try first to score 110/140 in our column.

Moreover, bidding 2♦, with your system, you still get the chance partner bids 2NT (if I can't show my club shortness on this I'll of course bid 4♥ now) or 3♥, on which I think bidding 4♥ is now even money.

[Fluffy]

There was a simulation not so long ago where partner rated to have heart fit based on that we have crippled the low hearts deck and only honnors are left.

Ths is borderline IMO, IMPs make me think 3♦ is better.

[ONEferBRID]

Jlall, on Oct 25 2009, 03:07 AM, said:

I would invite game (3D in your system).

What is the difference between 3♦ and the following invite:
1NT - 2♦
2♥ - 3♥

[benlessard]

Agree with dellache

Not vul i would just bid 2D. Since he going to super accept with 4 trumps and a minimum i dont see why we should stretch on both side. Im trying to construct hands where game is at least 75% and its tough (note that i would like to declare because if im dummy the D switch is easy to find). Im willing to accept a small gap if it compensated by playing 2M instead of 3M/4M going down.

[kgr]

ONEferBRID, on Oct 25 2009, 04:31 PM, said:

Jlall, on Oct 25 2009, 03:07 AM, said:

I would invite game (3D in your system).

What is the difference between 3♦ and the following invite:
1NT - 2♦
2♥ - 3♥

We have 3♦ to invite.
1NT-2♦-2♥-3♥ is slam interest

[kgr]

Scoring: IMP

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1NT-3♦!
4♦!-4♥
Pass-(DBL)-All Pass
 
3♦= invite with 6c♥ or 6c♠
4♦= You can bid you suit (4♣ would have asked to bid transfer to suit).
4♦ bacause minimal in points and support, but good 5c♦ should compensate.
 
Loosing 1♣, 3♥, and 2♠'s for min 3.
Who to blame?: Both N and S stretched the bidding, or is N or S more to blame, or is this unlucky (that E was able to DBL it)?

[pooltuna]

kgr, on Oct 25 2009, 11:24 AM, said:

Scoring: IMP

---

1NT-3♦!
4♦!-4♥
Pass-(DBL)-All Pass
 
3♦= invite with 6c♥ or 6c♠
4♦= You can bid you suit (4♣ would have asked to bid transfer to suit).
4♦ bacause minimal in points and support, but good 5c♦ should compensate.
 
Loosing 1♣, 3♥, and 2♠'s for min 3.
Who to blame?: Both N and S stretched the bidding, or is N or S more to blame, or is this unlucky (that E was able to DBL it)?

either your partner doesn't understand your bidding system or he is an idiot

[gnasher]

I don't find it at all difficult to construct hands where game is more than 75%. Qxx AKx AKx xxxx is about 90%.

Giving him a more typical hand, Axx KQx KJx Kxxx doesn't fit particularly well or particularly badly, and game is above 50%. Axx Kxx KJx KQxx makes a poor game, but Axxx KQx Kx KQxx makes an excellent one. Partly that just tells us that 4333 shapes are bad, but it also suggests that this is worth an invitation, but it's fairly close.

[TylerE]

100% to North. You showed an invite and his in minimum in both support and high cards. If you don't pass this, is it actually an invite?

[dellache]

A fast sim with the best sim ever

cpp 20091025.dea | dpp | dealer
 [space] [space] [space] [space] [space] [space]Low [space] [space] [space]7 [space] [space] [space]8 [space] [space] [space]9 [space] [space] [space]10 [space] [space] High [space] [space] [space] Sum
Reject [space] [space] [space]52 [space] [space]290 [space] 1247 [space] 1891 [space] [space]1000 [space] [space] [space]162 [space] [space] [space]4642
Accept [space] [space] [space] 5 [space] [space] 79 [space] [space]563 [space] 1822 [space] [space]2067 [space] [space] [space]822 [space] [space] [space]5358
Sum [space] [space] [space] [space] 57 [space] [space]369 [space] 1810 [space] 3713 [space] [space]3067 [space] [space] [space]984 [space] [space] 10000
Generated 166176 hands
Produced 10000 hands
Time needed 237.01 sec

10000 boards, South opens 1NT (including some 5422 with guarded doubletons), and South accepts 3♦ when : 1. has 4+♥, or2. Has 3+♥ and 16+HCP, or 3. 17HCP.

I think understanding the above table is easy (x-axis = tricks by south in Hearts, Y axis = south accepts/rejects invitation).

Results tell you that (double dummy) :
a- when south accepts, he plays a 53.9% game (more than even money at this vul, maybe I was pessimistic in my previous post, but see below) ;
b- when south rejects he plays 3♥ making 8 tricks 26% of the time.
c- cost for the rejected 3♦ bid is (342*-2 + 1247*-4 = -5672 Imps)
d- cost when 4♥ fails : (2385*-5+84*-3 = -12177 Imps)
e- gain when 4♥ makes : +6*(3067+984) = 17334
f- average gain of the 3♦ bid (c+d+e) = -0.05 imps per board.

(Here we compare the 3♦ bid to the case where south must transfer 2♦ into 2♥ and play there).

So 3♦ is not so costly at first but we didnot take into account the fact that :
- rapid check of single dummy boards on these cases seem to give advantage to declarer (so -0.05imp rather optimistic) ;
- declarer will also get doubled in 4♥ some of the time ;
- there is another strategy : bid 2♦ in the hope of hearing 2NT/3♥ as the original poster suggested.

I won't bug you with another figures, but here's is the result of the second strategy (bid 2♦, and bid 4♥ if pard shows 4+♥) : you gain 0.36 imp per board this time.

Altogether, bidding 2♦ then 4♥ facing a 4 carder is probably at least 0.4 imp above the direct 3♦ strategy.

The morale of this is :
"beware of the hidden cost of trial bids if you can stay low".
Hence I would give 60% of the blame to south (slight overbid), 40% to north (min+ hand, short trumps), and 100% to the pair, not taking full advantage of their system.

(don't know what the standard is on this board, so apologies if this is too long).
Cheers.

[bid_em_up]

I blame South 100% for not simply bidding 2♦ and passing 2H if thats what partner bids. If he bids anything else (accepting hearts), then I will get to 4H (retransfer, if available).

[Fluffy]

dellache your conclusions are biased.

-At game level dobule dummy defence is harder than declarer play. Making the right lead against the 1NT opener is not so easy.

-We expect opener to have a better criterium than just adding HCP with its hearts.

[eyhung]

Fluffy, on Oct 25 2009, 03:52 PM, said:

dellache your conclusions are biased.

-At game level double dummy defence is harder than declarer play. Making the right lead against the 1NT opener is not so easy.

-We expect opener to have a better criterium than just adding HCP with its hearts.

Actually, there was a recent article in the Bridge World on whether double-dummy defense / declarer play is dependent on level, and I believe its conclusions were, after analyzing expert play, that "declarer's advantage" shrinks as the level of the contract increases. You can see this most strikingly with the contract of 1NT, which is often described as the hardest to defend (and declare!). Against a major-suit game, expert defenders can achieve double-dummy defense a surprising amount of the time.

Also, while I agree it is not the best metric, HCP + hearts >= 19 is certainly a reasonable one -- the actual opener in particular would have benefited from it. One of the reasons I like to post sims + criteria is to get input from the accomplished players on whether my criteria are worthwhile. If you don't like the criteria, instead of just saying "this criteria sucks", how about suggesting a better one, one that you use? It will only take a few minutes to evaluate.

[dellache]

Fluffy, on Oct 25 2009, 10:52 PM, said:

dellache your conclusions are biased.

1-At game level dobule dummy defence is harder than declarer play. Making the right lead against the 1NT opener is not so easy.

2-We expect opener to have a better criterium than just adding HCP with its hearts.

Hi fluffy,


Warning : my answers may seem a bit harsh. They are not intended to.

1- I bet you haven't been working with SD/DD-simulators a lot. I did. I have been co-developing "dealer" (which is now used to simulate boards on the new BBO webbased-platform) with Hans van Staveren and others a few years ago. What do we really know about SD versus DD evaluation now ? A lot, even if not much has been published yet. Eugene has already said that the higher the contract, the more the balance will be in favour of declarer (if you think about the extremes, barring the lead, declarer has almost ever the advantage playing the slams double dummy). That's of course true. My personal experience when I still had time to do research was that the trigger was around 10 tricks on offense (3 on defense). To do that, I did a large scale comparison DD versus average human results on OKbridge (I didnot know BBO at that time).

The other way to do that properly is to make a fast "visual" DD versus SD comparison on a particular deal. Let's say you are sampling 10000 boards and study them DD. Take the 100 first ones, check the results one by one single dummy using common sense. There will be a bias, but it's now rather easy to evaluate it. For the deal we are talking about, I already told that the DD advantage was in favour of the declarer (he always guesses trumps, or spades when he has AT when he needs it).

That's the answer to your first point.


2- The second point is typical to what I call magical approach of Bridge. Points schmoints, so just counting your points and your trumps cannot be expert bridge and is of dubious value. We all would like to believe this, and that's why sometimes we accept to bid game on a 3♦ trial-bid with xxx Ax AKJTx Kxx. "Sry Pard, I know I had only 15HCP and a 2 card fit, BUT I had prime cards, a good 5cm, no isolated quacks.".
On the proposed deal, the best way to evaluate for South is to look at the honors he has in front of the stiff clubs... he doesn't know about.
Then of course you could downgrade/upgrade your hand looking at your stiff honor combinations, dull shape etc. The Dealer simulator already does that for you if you call K&R evaluation instead of HCP.
If you think the simple criteria "trumps + strength" sucks, what else do you suggest ? I would be glad to program it and run a new sim

Cheers.

[gwnn]

I hope I won't be LOL ed at but how can 1NT be both the hardest to defend and the hardest to declare?! I am usually happy to declare 1NT and give away between 1.5 and 4 tricks on 1NT defence. But I guess I'm just a datapoint.

[gwnn]

I'm surprised nobody has mentioned

http://www.jeffgoldsmith.org/cgi-bin/knr.c...xx+Ax+AKJTx+Kxx

yet

[Fluffy]

A common evaluation opposite a 1-suiter is to devaluate Qs and Js in the side suits specially if unprotected, and upgrade the aces. Upgrade honnors in the trump suit.

And well, you know that Ax xxx AQx KQ10xx is gonna give you discards most often.

Giving concrete examples is silly. I just wanted to point out that partner is smarter. I didn't mean that partner is perfect nor that your criterium is not good.


I have seen people simulating and calculating partner's decision by just saying that he bids game when you make game. That is clearly wrong obviously. But my point is: everyone modifies the data to prove their own point.


your results showed -0.05, and I just say that if you add a bit more criterium for the final decision, you might find it worth inviting.

EDIT: I though this was a close decision and it was already proven, so I am happy. I forgot to mention that I stand correced about double dummy solvers. If you are sure they help declarer they surelly do.

[eyhung]

dellache, on Oct 26 2009, 12:14 AM, said:

Eugene has already said that the higher the contract, the more the balance will be in favour of declarer (if you think about the extremes, barring the lead, declarer has almost ever the advantage playing the slams double dummy).

That's the opposite of what I said. In general, the LOWER the contract, the MORE advantage declarer has in real-life.

The article is "Declarer's 'Advantage'" by Jeff Miller in the May 2009 Bridge World. In this article he talks about his analysis of 48000+ results from 822 deals played from the Shanghai world championship. At the 1-level, declarer should make 63.2% of the time but actually makes 68.8%, for a declarer advantage of 5.6%. This advantage always decreases as level increases. At the 4-level, declarer makes 2.5% more contracts than he would make double-dummy, so if your sims say 4H makes 52.5% of the time, in reality you will make 55%. The 5-level is roughly even with double-dummy, and in the slam zone, the advantage shifts to the defense by 3-4%.

His conclusion is that when you are evaluating contracts by simulation, you should adjust for declarer's advantage.