The Full Deal
Say that you played a spade to the ten and Queen, and East continued diamonds (you ruffed again). Now Ace of hearts, ten of hearts ruffed in dummy, Ace of spades, and the King did not fall (but clearly East has it, else West would have opened the bidding). East started with three spades, six hearts according to the bidding, and three diamonds that you’ve seen, so you would know to play West for the club length (King of clubs, club to the Ace, and – East having shown out — finesse West for the Jack). Plus 420 (ten tricks) earns a 94% matchpoint score. Minus 50 (down one) would be 25%.
However, at our table, our opponent South – playing without thinking — ran the nine of spades at trick three (losing to the Queen), ruffed the diamond return, and then played a spade to the ten (losing to the King). East played back a spade, and declarer ended down one. Deal PS036.
To explore alternative lines of play and defense, use this link: https://tinyurl.com/5n87yvx2