A ruffing finesse occurs when declarer holds a sequence in one hand and a void in the other. In this layout, South is on lead with spades as trumps:
South has two natural diamond losers, but can shed them by leading the Q toward dummy.
If West covers with the K, then dummy ruffs. South comes back to hand with the A and discards dummy»s diamonds on the QJ.
If West ducks the Q instead, declarer throws a diamond from dummy and leads another heart, thereby repeating the ruffing finesse.
Figuring dummy for a spade singleton or void on the auction, South optimistically barrels into 6. West»s opening lead is the 3, won by East»s ace. At trick two, East returns the J.
South knows that East should have played the K (the lower of two touching honors) casino if holding both the ace and king. South can also count 22 HCP between his hand and dummy, and East has just advertised 5 HCP. Therefore, West should hold both the K and K to justify an opening bid.
South, then, should spurn the club finesse and try a ruffing finesse in spades. At trick two, he wins the A and proceeds to draw trumps, finding them 1-1.
South now leads the J through West for a ruffing finesse. If West covers, then dummy ruffs and South returns to his hand via a trump to play spade winners, dumping club losers from dummy. If West ducks the J, then South pitches a club from dummy and continues with the T. Either way, South»s losing clubs can be ruffed in dummy to make the contract. The full deal: