Takeout Doubles

Board 8
West Deals
None Vul
Q J 10 7
A K 9 7
A 9 5 3
4
A 9 5 2
J 4
K J
K 10 9 7 6
N
WE
S
8 6 4
6 5 3
Q 10 8 2
A Q 3
K 3
Q 10 8 2
7 6 4
J 8 5 2
WestNorthEastSouth
1Dbl1NT2
All pass   
2 by South

North's double promises support for all the unbid suits and an opening hand.
South, who would have bid 2 over partner's opening 1 bid, should therefore bid 2 .
South should draw 3 rounds of trumps and set up spades remembering to play K first, to avoid being blocked.