Takeout Doubles

Board 6
East Deals
E-W Vul
K Q 4 2
9 6 4
A 3 2
7 5 4
6 5
J 2
Q J 10 9 5
9 8 6 2
N
WE
S
A 10 9 8 7
K 10 7 5
8 6
A Q
J 3
A Q 8 3
K 7 4
K J 10 3
WestNorthEastSouth
  1Dbl
Pass1NTAll pass 
1NT by North

North's best suit is the opponent's spade suit so should bid 1 NT to show 6-9 HCP and a hold in spades. Lead is 7. Firstly, Declarer should play on clubs and later take a heart finesse.