There is an interesting defensive point to this deal from the European Junior Championships in Albena, Bulgaria. The auction featured a rather pointless transfer to clubs: East was presumably trying to discover if 5C might be a better contract, but with just eight high card points opposite a strong no-trump the five-level looks a long way off.
North led the three of hearts against 3NT and South won the ace and returned a heart. North allowed the jack of hearts to win, so West led a club towards dummy. North ducked, the queen scored, and declarer crossed back to hand with a top diamond to lead another club to the king, noting the fall of the ten. North now played a third heart to the king. A club forced out the ace, and North cashed the thirteenth heart, but declarer more than enough tricks with two spades, two hearts and three tricks in each minor. Could the defence do better?
North should cover the jack of hearts at trick two, forcing out the king and removing an entry from dummy. Now when he ducks the first club the suit can never be established and cashed because, as it happens, there is only one diamond entry to dummy. But the first mistake was South’s. If he saves his ace of hearts to beat the king, inserting the nine instead, he holds declarer to one heart trick. The suit is frozen, but the defenders can play on spades to establish the winners they need.