Tuesday, July 24, 2012

This Fiish Will Bite on Anything!

I was salivating over a 3 NT contract last week at the Wednesday game at Temple Beth El. I could see that everyone would be in 3NT, so I dedicated myself to getting that extra trick that must be lurking somewhere in this computer generated hand. Here are the N-S hands:



The opening lead from West was the heart 3, I put in the J and it held. I knew that the odds of the diamond suit splitting 3-3 were about 35% and the 4-2 break was 48%. The true odds of running diamonds from the top was about 39% since the JT doubleton in either hand would also work holding the 9 of diamonds. If I get lucky and run 5 diamond tricks, maybe somebody will discard a spade and help me out.

I started with the Ace of diamonds and I see Greg Giles, who is sitting East, smoothly play the Jack of diamonds. Greg was someone I did not know, but his face was totally innocent, so I credited him with a stiff Jack and decided to go after West’s ten that was bracketed by my Q-9. I came back to my hand and led the 3 toward my Q-9 tenace and see Greg taking my trick with the 10 of diamonds. Did he start with the JT? Oh no, worse than that, he had played the J from JT5 and I went for it like a rat to cheese!

While clearing my head, I hear a loud roar of laughter at the table. I am about to lecture my opponent for gloating and look across the table and see it is my partner Jim Bailey who is laughing telling me I got suckered by a clever false card. Well, at this point I am thinking that if I have to go down, there is nobody else I would rather take with me than Jim.

It is all very humiliating: Here I am the Prince of Probabilities being taken down like a novice. Still licking my wounds in the aftermath, and clinging to a faint hope that I can patch up my reputation, I turn to the Encyclopedia of Bridge looking under suit combinations. Sure enough, I found the exact card holding with the following play advice:

1. For 5 Tricks play the top honors hoping that the Jack and Ten drop in 3 rounds. It is a 39% probability.

2. For 4 Tricks (a safety play) start by leading small to the 9 in case East is void or has a single that is lower than the 9. This play will take 4 tricks 90% of the time.

3. When playing against players who are not devious and unlikely to false card the Jack when holding JTx, cash the Ace and if you see an honor drop from East, finesse the 9 on the next play.

So my claim is that I did not make a mistake or get suckered, I just misjudged Greg’s character. He is in fact a deceiver and a ruthless one at that. How did it all work out? We got a zero on the board, but I was able to swallow my pride and recover for a high finish. The moral of this story is never trust an innocent face. Or better yet, just mindlessly lay down the top 3 honors no matter what you see.

If I substitute the ten on the board in place of the nine, should you now finesse the ten or play the diamond honors from the top? I don’t have to look in the Encyclopedia of Bridge to know that finesse is a 50% probability, so at first blush it looks like the finesse is the percentage play. But wait, adding the 10 in place of the 9 changes everything, since the Jack becomes a significant card. No defender would play the Jack from Jx since it would give declarer the whole suit, and this changes the odds on the 3-3 break from 39% to 52%. Thus, playing the honors from the top is 2% superior to taking the finesse. For those who want the mathematical explanation of these phenomena, see my blog post of September 23, 2007 entitled “The Odds and Ends of Bridge (Post Graduate Course).”

Will all of this convince Jim Bailey that I am not a fish? Absolutely not, so perhaps I should just admit that I got bamboozled by an innocent face. A pretty face works equally as well, so powder your nose ladies.

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