Losing control by unnecessary ruffing with long trumps

Losing control by unnecessary ruffing with long trumps

A 5
Q 6 5 4
10 5 4 3
6 4 3
N
W   E
 
S
4
K J 3
K Q J 6
A K Q J 10

Contract:

5 by South

Lead:

K

Somehow you have ended up in the best contract. You have two missing side suit aces. Plan the play.