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
  1♠Dbl
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.