South put up dummy's queen to continue with a low heart for the queen and king. West exited with the ten of spades as declarer won and advanced the nine of diamonds towards the table. West rose with the ace to return a diamond for the king. The ace of hearts brought the bad news and, when South played a low club for the jack and ace, the game was down one, N-S -100. The 4-1 trump break had doomed the contract and it was virtually impossible for N-S to stop short of game.
Perversely, 3NT is likely to yield nine tricks since West will be pressured at every turn.
North's decision to respond one diamond would not be a popular action at many tables. A majority of players would ignore diamonds to respond one heart and would become declarer in the major suit game. East would begin with the jack of diamonds where the result would be down one when North guesses clubs correctly. The minor suit response was reasonable since diamonds were stronger than hearts. A heart fit would not be buried because opener would rebid one heart with a four-bagger.
If East interjects with a one spade overcall, a double by South can be employed to disclose a four-card heart suit.