While fourth down in your longest and strongest suit is often the best lead, you should pay attention to the auction before making that decision.
Scoring: Matchpoints (Pairs)
BIDDING: After North made a weak preference to diamonds, South finally showed extras by jumping to 3NT.
PLAY: I was sitting West and a club, the unbid suit, seemed the obvious lead. However, after reflecting on the auction I decided declarer was prepared for a club, likely holding three or four, and was probably short in hearts. (If he held a balanced hand, he would have opened 1NT or jumped to 2NT over the heart response.) I backed that hunch by putting the jack of hearts on the table. Declarer won the king as my partner encouraged with the deuce (upside-down signal). Next, declarer misplayed diamonds by starting with the ace from his hand and low toward dummy. He was now in trouble.
He went up with the king of diamonds and took the losing club finesse into my hand. I continued with the nine of hearts and declarer rose with dummy’s ace. Next he led a low spade to his ten allowing me to win and continue with my last heart. This gave us one spade, three hearts, two diamonds, and one club. A very flustered declarer had to enter down three on the score card.Most N/S pairs made either nine or ten tricks in notrump after receiving a club lead.
This declarer could have done better but the hand shows how important the auction is to the defense.