This deal features a very rare end position.
West led a heart against three notrump, won with the ace in dummy. Declarer led a diamond to the jack, then cashed the ace and queen of clubs, hoping for two club entries to play diamonds through East again. However, when clubs split 4-1 he played a diamond to the queen and ace. East cashed the spade ace and switched mysteriously to a diamond. South was now able to cash red suit winners throwing a club from dummy leading to the following end position with East to discard.
If East discards a spade then South cashes the spade king, crosses to dummy with the king of clubs and wins the ten of spades.
If East discards a club then South plays a club to the king and a spade back to hand and wins the nine of clubs.
This ending is a criss-cross squeeze. It is uncommon because it needs an unusual combination of blocked suits.