West leads the K♦ (promising the Q♦ ). You are forced to take it with the A♦ . Now what! You have one losing ♦ and one losing ♣ in your hand. How do you get rid of one of those losers?
If you lose the lead, the opponents immediately cash their Q ♦ and A ♣ (down 2).
The only way is to hope for a 3-3 split in spades, and throw the losing ♦ or ♣ on the 4th spade. Did you try that and still not get it right?
To pull all the trump immediately you would have to lead the K ♥ and overtake it with the A ♥. All good unless you have a 4-1 split with trump (still down 2).
How about cashing the K ♥, then working on the spades?
But how do you work on the Spades? You can finesse it two ways....which way did you choose, and did it work? Do you pull trump when you get to your hand?
Solution: Take the first trick with the A ♦
Then lead K ♥ , pulling 1 round of trump.
Lead low ♠ from board to 10 ♠ in your hand. (Watch discards from E & W to see what spot cards they are throwing. Low from each side may indicate each player has 3 spades.)
Pull remaining trump.
Now lead K ♠, while keeping fingers crossed! All players follow, so play the J ♠, overtaking with the A ♠ on the board. Now the last spade is good and you can throw the ♦ or ♣ from South's hand and make the contract.