[jdeegan]

I will pay $20 U.S. to the first person who can construct and post on this thread a complete bridge hand consistent with the constraints imposed by the bidding in which the opening lead of a small ♠ is necessary to defeat a contract of 6♥. Your hand is:

Scoring: IMP

2♣-P-2♦-P
2NT-P-3♦-P
4♥-P-5♦-P
6♥ -P-P-P

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2♣ was artificial and strong, 2♦ waiting, 2NT 22-24HCP, 3♦ transfer to ♥, 4♥ super-accept, 5♦ cue bid, 6♥ to play

RHO, Jimmy Cayne, is constrained the have a normal 2NT opener (no singleton or two doubletons) with 22-24 HCP. His jump to 4♥ showed a max with 4 ♥. His jump to 6♥ showed the ♠ ace, a ♣ control, and excellent ♥ (AKxx, AQJx, KQJx) and likely a max in high cards. LHO, Chuck Burger, showed a ♦ control (A or KQ) and enough HCP so that the combined total for the two hands must be at least 31 for purposes of this contest. Pard cannot be void in ♠.

To summarize the constraints:
- 31+ HCP for the two hands
- 23-24 HCP for RHO
- 4 good ♥ for RHO
- ♣ control for RHO
- ♦ control for LHO
- 5+ ♥ for LHO
- no ♠ void

Have at it gang. The winner (if any) will be paid through a funds transfer via BBO.

jdeegan

[jdonn]

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jdonn pls

[Cyberyeti]

jdonn, on Mar 4 2010, 07:29 PM, said:

Dealer: ????? Vul: ???? Scoring: Unknown

♠ xx ♥ Qxxxx ♦ AQxx ♣ xx ♠ KTxxx ♥ T ♦ xxx ♣ xxxx ♠ Qxx ♥ xxx ♦ Txx ♣ ATxx ♠ AJx ♥ AKJx ♦ KJx ♣ KQJ

jdonn pls

The question says a small spade lead is required, here won't the K do too ?

Almost requires partner to have stiff Q or a Q holding he can be squeezed out of if you lead the K.

[jdonn]

I don't think that's what was meant but I suppose you're technically right. Maybe something with AJx of spades and AJT of clubs with south and xx xx with north, where the king lead ducked would make the club loser go away but a non-spade lead would make the spade loser go away. But if we give partner 7 and we have 3 the opponents can't have 31.

[karlson]

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How'd I do?

[rogerclee]

never mind

[jdonn]

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Do I win because in karlson's example south might have the 8 of spades and be able to set up a diamond discard? DIRECTOR PLEASE

[karlson]

Nice, good catch.

But I realized there's no reason I can't give south the ♦J. Now they have 32HCP, so surely that's worth some extra credit.

---

[Cascade]

I wonder what that spade x is in dummy?

[jjbrr]

Pay dat man his maney

[Fluffy]

cayuga's puzzles don't give money .

[jdeegan]

Congratulations jdonn!!! for presenting the first valid answer. Well done karlson for a second valid answer!! My point in presenting this exercise (at the cost of $20 american, by the way) was to illustrate how hard it is to find hands where a ♠ lead wins. Just the odds of finding pard with the ♠ queen are pretty low, plus you need so much more for it to be a winner. Meanwhile, the probability of giving up a trick by leading a ♠ is way more than 50% - maybe 75%. Best hope on this hand is to hang in there, hoping to get your ♠ trick and maybe another from pard - ♥Qxx or ♦K or ♣A. To me a ♠ lead on this hand is so low percentage as to be a clear error.

[karlson]

My guess is that it took jdonn about 30 seconds to come up with his example.

That said, since this hand has inspired such strong opinions, I thought I'd try to do some statistics.

I dealt 1000 hands consistent with jdeegan's criteria, except for the spade void part (which may not be perfect but do not seem ridiculous to me). 6♥ was beatable 66 times out of 1000.

12/66 any lead beat it (by any lead here I mean any suit, 6 of these you could lead any card but the ♠K.)
9/66 a spade was the only lead to beat it
0/66 a heart ....
6/66 a diamond ....
5/66 a club
33/66 anything but a spade
1/66 a club or a diamond

While the usual double dummy qualifiers apply, I think the numbers strongly suggest that one shouldn't just dismiss jdeegan's point.

Edit: 10000 hands give only 141 hands where it's beatable at all, so I probably overestimated that probability, but the relative gains of the different leads seem pretty much the same. 85/141 hands any lead but a spade is necessary. 11/141 a spade was the only lead to beat it.

[jdonn]

Thank you for the contest! My favorite part was when you said "the winner (if any)" as though this was an impossible task haha.

Karlson you ran 1,000 and a spade was the only lead 9 times, then you ran 10,000 and a spade was the only lead 11 times? And it was beatable overall 66 out of 1,000 but 141 out of 10,000? Um..... something doesn't seem to match up...

[karlson]

I think it's right, it's going to be very noisy with such a low probability of success. I ran 10000 again and I got 107 beatable, 10 must lead a spade, 69 anything but a spade. I can run a million overnight just for kicks.

I think the first 1000 was just an incredibly lucky set. I didn't change the code at all.

Obviously the probability of beating it in practice will be rather higher, since these hands include plenty of hands where they're just cold for grand and might try to bid it. Could try to do something a little more intelligent there, but I don't see why it would affect the spade/non-spade decision.

If someone wants, they can see the 107 hands from my last set where 6h was beatable and see if they think there's a significant double-dummy bias.

http://www2.decf.ber...jdeeg_prob.html. The winning leads are in the corner where the makeable contracts usually are.

[helene_t]

karlson, on Mar 5 2010, 07:54 AM, said:

My guess is that it took jdonn about 30 seconds to come up with his example.

That is 2400/hour and jdonn is not even a pro. I think bridge players earn outrageous amounts of money. Something needs to be done about it.

[hanp]

How can jdonn have won this contest? What does the word "necessary" mean to you in "in which the opening lead of a small ♠ is necessary"?

[gwnn]

jjbrr, on Mar 5 2010, 04:13 AM, said:

Pay dat man his maney

EPIC MOVIE

[Fluffy]

the constraits favor non spade leads, but if you throw some 5422's and 6332's into the 2NT opener the things will tend to move towards spade lead of course.

But anyway the simulation suggests that spade is way behind from other leads, so even though it should be a bit better it won't be best.

[gnasher]

hanp, on Mar 5 2010, 11:46 AM, said:

How can jdonn have won this contest? What does the word "necessary" mean to you in "in which the opening lead of a small ♠ is necessary"?

I think Cascade won it.