Takeout Doubles

Board 4
West Deals
Both Vul
A 5 3
K 9 7 5
10 5
A J 6 3
K 4
A J
K J 9 4 2
Q 7 5 2
N
WE
S
8 6
Q 10 6 4 2
A 8 6 3
8 4
Q J 10 9 7 2
8 3
Q 7
K 10 9
WestNorthEastSouth
1Dbl12
All pass   

With 6 spades and 8 HCP, South has enough to invite game, so bids 2 . North is minimum and declines the invitation.
Lead is 2 from the longest and strongest suit. Declarer draws trumps and plays West, the opener, for the Q. Therefore play the K then 10 and let it run if West
does not cover with the Q.