North opened One Diamond, East (wisely) passed, and South responded One Heart. North's rebid of 1NT showed, in the modern style, 15-17 points; instead of raising to game, his partner explored with a conventional Two Clubs. North's response of Two Hearts showed a minimum but promised three- card heart support. South could still have bid 3NT but - perhaps eager to play the hand - preferred the heart game.
West led the four of spades against Four Hearts and, after taking his two tricks in the suit, East led a third round to South's jack. A trump to the king revealed the bad break but declarer saw that he could still be in business if East had started with four clubs, when there might be an end play in trumps. East duly obliged by following to four rounds of clubs on which South threw two of his diamonds.
Next came the ace of diamonds and South breathed a sigh of relief when East followed suit. A low diamond from dummy saw East ruff with his seven, and now South made the key play. Instead of over-ruffing (which would have left East with two sure trump tricks) he under-ruffed! East was left on lead with only _9 8 and was forced to concede the last three tricks.