Sleeping on the Couch

The Continuing Misadventures of Dave Playing Bridge with His Wife, Anne

By Dave Caprera
Denver, Colorado

Our Bidding
Affected My Play


Playing in the finals of a regional Knockout you pick up:
♠xxxxx ♥xx ♦Qx ♣QJ10x
Your RHO is dealer and the opponents bid as follows:

RHO     You       LHO        Partner
1♥        Pass      2♣*         Pass  
2♥        Pass      4NT        Pass
5♥        Pass      5♠           Pass
6♣        Pass      6♥           Pass  

*2♣ was game forcing
2♥ promised six
4NT was keycard in hearts
5♥ showed two keycards without the trump queen
5♠ promised all the keycards and asked for the number of kings
6♣ showed one outside king
6♥ ended the auction.

You lead the ♣Q and dummy tables the expected very good hand:

Declarer wins the ♣A, partner showing an even number of clubs, plays the ♥Q and a heart to the ♥A (partner following twice, ♥2-♥10), plays a diamond to the ace, and ruffs a club.
Did you unblock the ♦Q? Did you consider unblocking the ♦Q? What percentage of the time do you think an expert defender would unblock the ♦Q?
Let’s try it again, only this time you hear the following auction:

South    West      North       East
1♥        Pass      2♣*         Pass  
2♦*       Pass      2♥           Pass
3♦         Pass      4♦           Pass  
4♠         Pass      5♦           Pass
6♥        Pass      Pass         Pass

*2♣ is artificial game force
*2♦ showed a sixth heart (we call it BOSCO)
2♥ set trump
3♦ and 4♦ were natural
4♠ was six card keycard (counting the ♦K as a keycard)
5♦ showed two keycards.
6♥ ended the auction.

If declarer plays in the same fashion, West knows that the opponents have a diamond fit and that East has the ♦K. Now it would be a clear error for West not to unblock the ♦Q on the first round of the suit.
(BOSCO stands for “Balanced or Standard Club Options.” It is also the chocolate syrup Alfred Hitchcock used as blood in the famous shower scene in the movie “Psycho.” 1M - 2♣ is an artificial game force.)
Here is yours and the N/S hands:




I was declarer South. My LHO was a young bridge pro that I did not know. I had two possible lines: I could strip the black suits and play to dummy’s ♦8, hoping West had the ♦10 (or East had the singleton ♦10). Or I could play the ♦A, then strip the black suits planning to endplay either opponent to give a ruff-sluff for the 12th trick. But if you strip the black suits before you play the ♦A, even the most somnolent West is going to find the unblock. And you can’t really sit there thinking, thus also giving West time to think, before you play the ♦A. It is now or never.

My esteemed editors have previously informed me that you, my loyal reader, does not appreciate lengthy calculations, so I will try to be brief. First, you need to make some assumptions. If East had a diamond void, he would have doubled. If West had a singleton diamond, and knowing the opponents are off a keycard, he would have led it. West will duck with ♦KQx when you lead up to the ♦AJ8x. And if you play to finesse the ♦10 and West plays the first round ♦K or ♦Q, you will cross back to your hand and play to the ♦8, as ♦K10x and ♦Q10x are twice as likely as ♦KQx.
If you accept those assumptions, and once you’ve seen trump break 2-2, you can determine the likelihood of success by listing the 32 possible diamond holdings for West times the probability of each occurring and the outcome of either line of play. The two lines are quite close. If West always unblocks when you play the ♦A first, the finesse of the ♦10 is about 8% better.
However, if West fails to unblock with ♦Kx or ♦Qx approximately five times out of eight, the ♦A first is the winner.
So now let’s go back to the auctions. In the “`standard auction,” where the defense doesn’t know about the diamond fit or the location of the ♦K, it is possible that declarer is about to `misguess the ♦Q. I make the likelihood of West unblocking as “pretty low.” But in our BOSCO auction, with all the available information, I was now sure my young professional LHO was finding the unblock. (Annie and I play BOSCO at my insistence. If left to her, our auction would have been less revealing. If our scientific auction had cost us a slam swing, you know where I would have been sleeping.)
At the table I played on instinct and cashed the ♦A. Fortunately, the ♦KQ10 were with East and the contract (which had also been bid at the other table) could not be made. We won the match and the event. It is better to be lucky than to be good and, once again, winning kept me from sleeping on the couch.