East, playing five-card majors and a strong no-trump, opened One Club and Goncalves (as South) ended in Four Spades. West led the 2J and this ran round to South's king. Declarer unblocked his !A and finessed dummy's 29, losing to the ace. East switched to #Q and declarer won, crossed successfully to 2Q, and cashed the two top hearts to discard diamonds from hand. Next he led 42 from dummy and, when East played low, put in the seven, hoping to pick up 4Q,9,x or 4K,9,x with East later.
It may seem insignificant, but West had followed to the third round of clubs with his six, retaining the 10. So East became marked with only a three-card club suit and a weak no-trump hand. When 47 won the trick for declarer, it now seemed extremely likely that East had started with a 4-4-2-3 distribution. Goncalves exited with a diamond to the jack and West, now forced to lead a minor suit, chose a diamond.
Declarer ruffed in dummy with the six and East was left with 4K,Q,9 and !J. He did his best by discarding a heart, but Goncalves under-ruffed with 43 and led the bare 410 from dummy. East covered but was allowed to hold the trick and now his forced trump return allowed South to finesse the jack and so collect the last two tricks.Reuse content