North-South reached a contract of six spades against silent opponents. The opening lead is the 9 of diamonds. The reader is invited to contemplate the best line of play prior to proceeding further:
' J 10 6 4
'* A Q J
'¶ A J
'£ Q 7 6 5
' A Q 9 8 5
'* 7 5
'¶ Q 2
'£ A K 10 3
On some hands, declarer is confronted with an array of alternatives. This is one. There are possible finesses in every suit. But, since a finesse should always be avoided if there is a better alternative, this is how one's reasoning ought to go.
It is not hard to see that a successful diamond finesse at trick one will not eliminate the need to take a heart finesse later, whereas a successful heart finesse (when repeated) will enable the finesse in diamonds to be avoided, since declarer's diamond loser can be discarded on dummy's extra heart winner. For convenience, here is the West hand:
' K 3
'* K 9 6 4
'¶ 9 8 6
'£ J 9 4 2
So, win the ace of diamonds at trick one, enter the South hand with the king of clubs, and then finesse the jack of hearts. That works. What now?
If you try to return to your hand with a second round of clubs, East can ruff, cash the king of diamonds, and you will still lose a trick to the king of trumps to go down two.
But that would have been unnecessarily risky. Instead, you should return to the South hand with the ace of spades, then repeat the heart finesse. You then discard the queen of diamonds on the ace of hearts, take the precaution of ruffing the jack of diamonds in hand, and play a second round of trumps.
On the actual deal, West wins the king of spades as East follows suit. Since both red suits have been eliminated, you also have obviated the club loser. Whatever West plays, you score up the rest of the tricks. Careful play is rewarded.