Do what you must, even if painful

Donald Rumsfeld said, “There are known knowns. These are things we know that we know. There are known unknowns. That is to say, there are things that we know we don’t know. But there are also unknown unknowns. There are things we don’t know we don’t know.”

Now make a list of things you don’t know you don’t know!

At the bridge table, we sometimes have to decide what to do when we do not know who has which key cards. At other times, though, we will know who has what if an opponent is careless with the card that he plays.

As a simple example, you lead from ace-10-fourth against no-trump. Dummy has two low cards. Your partner plays the jack and declarer wins the trick with the queen. Who has the king?

It must be declarer. Now let declarer win the first trick with the king. Who has the queen?

You do not know, because partner would have played the jack with or without the queen.

With that hint, how should the play go in four spades after West leads the heart nine?

East opened two hearts to show a decent six-card suit and 5 to 10 high-card points.

If South plays the heart two under East’s ace, East will know West led a singleton. East will return the heart four, his lowest card being a suit-preference signal for clubs. West will ruff, cash the club ace, and continue with another club for down one.

Now go back to trick one, when South must smoothly drop his king under East’s ace. East is quite likely to shift to a diamond, after which declarer takes seven spades and three diamonds.