Preparing master card in suit as an entry

Preparing master card in suit as an entry

4 3
A 4 3
7 6
A 9 8 7 5 4
N
W   E
 
S
A K Q J 6 5
K J 2
A K
3 2

Contract:

6 by South

Lead:

Q

An entry in the suit itself can only be used for ruffing if the suit opposite can be voided without relinquishing the lead.

We win the first trick and draw trumps in three rounds. Now what?