East should make 11 Tricks here but not everyone did.

You probably get the ♠ A led and then should as always Count (losers in a Suit contract) and Plan.

You have four possible losers: ♠ A, ♠ K, ♦ K and ♣ K.

If South continues with the ♠ K and a third Spade 11 Tricks are easy. Overruff North, Draw Trumps in two rounds ending in hand. Play ♦ Q to finesse the King and use Dummy's last two trumps to ruff your fourth Diamond and the ♣ Q (or discard them on the ♠ Q J)

If South switches to a Trump then the ♠ K is marked and you should lead a low Spade towards Dummy setting up the ♠ Q J for a discard. If South ducks you still play the SJ next discarding CQ.

If South leads a Trump you have a dilemma.

You do best to draw trumps then lead a low Spade twice towards Dummy. This gives you an all important Spade discard if the ♠ A K are split or are both with South. You can always revert to the Diamond finesse if needed.