Sunday, October 17, 2010

Match 2 - Board 25

Board 25
Opponents vulnerable

♠ J 6 5 3 A J 7 Q 10 7 ♣ Q 10 4

Two passes to me. I pass. LHO passes. Great! I've been dreading this hand since I started this blog. How do I find something instructive to say about a pass-out?

Actually, there is something instructive to say. If we let partner open a light 12-14 one notrump and buy it, it turns out East might be presented with quite an interesting defensive problem (though a moot one as the cards lie):


NORTH
♠ J 6 5 3
A J 7
Q 10 7
♣ Q 10 4




EAST
♠ A 7 4
6 5 4 3
9 8 4
♣ A 9 7


WestNorthEastSouth
1 NT
(All pass)


Partner leads the deuce of hearts. Declarer plays low from the dummy, you give count with the six, and declarer wins with the ten. Declarer plays the deuce of diamonds--five--queen--four, then leads the ten of diamonds. You play the nine. It's important to play this card, so partner will know for sure you don't have the jack and will have an easier time counting declarer's hand. Declarer plays the three, and partner wins with the ace. Declarer presumably has either king-jack fourth or king-jack fifth of diamonds,

Partner continues with the eight of hearts--jack--three--king. Declarer leads the six of clubs--deuce--ten.

If we assume that partner has four hearts, that his count card in clubs is honest, and that declarer is not off-shape, then declarer must be 3-2-4-4. Any one of those three assumptions might be wrong. But, for the time being, we'll credit declarer with that shape. Declarer has five to seven high-card points unaccounted for. (Ignore for the moment the fact that we know he doesn't have them, since he didn't open actually one notrump at the table.) That means he has one of three hands (where the '?' could be either the club jack or a small club):

(A) ♠ Q x x K 10 K J x x ♣ K ? x x
(B) ♠ K x x K 10 K J x x ♣ K ? x x
(C) ♠ K Q x K 10 K J x x ♣ ? x x x

He would probably attack spades, not clubs, with (C). So let's give him either (A) or (B). In either case, he will make nine tricks if you take your ace and continue hearts. If he has (A), however, you can hold him to eight tricks by ducking.  If declarer continue clubs, you win and play a diamond. Declarer's entries are tangled up. He must leave either dummy's heart or his long club stranded.  (It might also work to duck the second club. But I don't see any particular reason to verify that fact.  As in chess, it's easier to analyze positions where you take control.)

Is this the interesting problem? Not yet. This is pretty straight-forward so far. Let's continue. You duck. Declarer plays a low club from dummy. You hop with the ace--eight--five. You shift to the eight of diamonds--king--six--seven. Declarer cashes the jack of diamonds, plays a club to dummy's queen, and cashes the heart ace. We are down to this end position:


NORTH
♠ J 6 5
--
--
♣ --


WEST
♠ ? ?
Q
--
♣ --


EAST
♠ A 7
4
--
♣ --


SOUTH
♠ ? ?
--
-
♣ K



If declarer has the spade queen, you have the rest. But what if he has the king? What should you do when declarer leads a low spade from dummy? If you duck, declarer can take ten tricks. If you hop, you hold him to nine. Clearly you should hop if declarer has the king alone. But what if he has king-ten? Then you must duck. If declarer finesses the ten, he will take only eight tricks. True, he still can take ten tricks by playing the king, but he probably won't precisely because you might hop with the ace if you had it. The king can't be any better than 50%; and the ten can't be any worse. So this isn't even a game-theoretical problem. Depending on what East is inclined to do, the ten is either a better play than king or equally as good. The ten is unambigously declarer's percentage play.

So what should you do as defender? If you trust partner, you should duck. Partner is double-dummy at the point you return a diamond. If he has queen-ten of spades, he can anticipate your problem. He knows good and well he doesn't want you to duck when declarer leads a low spade off dummy. So, when declarer cashes the last diamond, he should throw the ten of spades to let you know declarer doesn't have a guess. If a trustworthy partner doesn't throw the ten spades, he doesn't have it. So you should duck.

Is that the interesting problem? No. This is still pretty routine stuff. The interesting problem comes if declarer doesn't cash the last diamond. What if he decides not to give your partner a chance to discard? Suppose he wins your diamond return and immediately plays a club to the queen to cash the heart ace? (This line does involve some risk. We'll leave unanswered the question of whether declarer should actually do this or not.)

Now the only way partner can communicate with you is through his choice of plays on the ace of hearts. How should he get the message across? I suspect that most experts would use suit-preference. When declarer cashes the heart ace, they would play the queen to show the spade ten and the nine to deny it. I think to signal this way is a mistake. Suit preference will work in this particular case, but only because we lucked out. It happens, by sheer accident, that it is a black suit we care about.

Suit preference works just fine when there are two suits under consideration. When you are concerned with only one suit, however, it doesn't always work so well. It does work sometimes. If spades is the suit you are worried about, you can certainly play high for "yes" and low for "no," and vice versa when clubs is the suit you are worried about. But what do you do about the red suits? In this deal, what if we simply switch the spade and diamond suits? How would you signal in hearts to show or deny possession of the diamond ten?

When there is only one suit in play, I think the proper signal to use is surrogate attitude - a sort of "Smith echo" for the relevant suit. So I agree that a high heart should show the spade ten, but for a different reason than everyone else. The fact that the suit is spades has nothing to do with it. It would also show the club ten or the diamond ten if we switched the suits around accordingly.

On the actual hand, as you already know, it doesn't matter whether you duck or not:


NORTH
♠ J 6 5 3
A J 7
Q 10 7
♣ Q 10 4


WEST
♠ K Q 9
Q 9 8 2
A 6 5
♣ 5 3 2


EAST
♠ A 7 4
6 5 4 3
9 8 4
♣ A 9 7


SOUTH
♠ 10 8 2
K 10
K J 3 2
♣ K J 8 6



The hand was passed out at all tables, so we get six matchpoints.

Score on Board 25: 0 (6 MP)
Total: 196 (65.3%)

Current Rank: 1st

3 comments:

  1. You have the play to trick 2 going D2-5-10-4, and then Trick 3 starts with the D10.

    This is more useful, in general, with aces.

    ReplyDelete
  2. Something was nagging me about the spade suit -- for instance, could or should West pitch the ten from ATx? As chance would have it, I was re-reading the April 2010 Bridge World issue later that day. Rosenberg has a letter to the editor, and Rubens has some musings on the suit (pp 23-24). We both missed the idea of running the jack. I wouldn't be surprised if there's a mixed strategy in it after all. The location of the ten seems to be a 50/50 proposition to the people who don't hold it, in the absence of a signal or pitch. It may well be a case of 50/50 randomization from both sides.

    ReplyDelete
  3. Thanks for directing me to that letter. I hadn't seen it. The musings are interesting, and I enjoyed seeing Rubens elevate Lowenthal to an eponym.

    ReplyDelete