You have six top tricks, so you need three more from the club suit. At trick two, therefore, you should play a low club from both hands. When you regain the lead, you will play another club toward dummy’s king-queen. This allows you to get three tricks whenever the suit is 3–3 or when the ♣A is doubleton in the West hand.
Why not play a club to the king at trick two? Look at this deal to see why:
After winning the opening spade lead, you play a low club to dummy’s king, and East ducks. If you return to your hand with a diamond to play another club to the queen, East will win the ace (or the jack if you play low in dummy), killing the suit. You can get back to dummy just once to drive out the enemy’s high club, but you lack another entry to run the suit and get your three needed tricks.
Note what happens if you play a low club from both hands at trick two. The defense can win cheaply and continue spades (or switch to hearts), but you will regain the lead and play another club to the king and ace. The defense can’t stop you from getting three club tricks if the suit is 3–3.
