# In Bridge, What is the Merit of Taking a “Double” Finesse?

Suppose I am declarer, and dummy has a "side" (non-trump) suit with AQx or AQxx, and I have xxx in my hand. I have been told NOT to finesse the Q (a 50-50 chance), except as a last resort, or late in hand. (And to "refuse" the finesse, probably taking the ace, if that suit is led in say, a NT contract).

Change dummy a bit to AQTxx. Now I'm told that I have a double finesse, because I am finessing against both the K and J. In such instances, I have been told that I SHOULD finesse (assuming that going twice to my hand to lead doesn't cause problems elsewhere). If the KJ are both with LHO, I win twice, if both with RHO, I lose twice, but most likely, I win one and lose one because the honors are split. If the opponents have a 3-2 split (a 68% chance), I can treat the lost finesse as a "ducking" play, and run the suit for four tricks after I clear it with the ace.

What makes the "double" finesse so much better than the "simple" finesse? Is it because the extra card in dummy might allow me to win a fourth (long) trick? Or is it because I have a second potential stopper in dummy if the first finesse fails? Is it in the double finesse I PROBABLY win once, whereas in the simple finesse I POSSIBLY win once? Or have I been given the wrong advice about double finesses?

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You have answered your own question in the last paragraph. The simple finesse gets nothing because you can only win the Queen if the King is onside, in which case you will come to it in the end anyway, and taking it may consume an entry, lose a tempo, and so forth.

In the second case you are, as you state, developing a possible long card, and (provided you put in the Ten) possibly the Queen as a winner if the Jack is right and the King wrong.

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Putting in the T is a key point. So with AQTxx, you have the chance/option of putting in the T. Whereas you don't with AQxx. – Tom Au Jul 19 '11 at 18:44