The Guardian,
How do you react to a hand such as this, as dealer at unfavourable vulnerability?
KQJ10972 
K754 
Q 
5
There are two main choices and one less orthodox one: four spades and one spade are the «normal» opening bids, or you can pass («only 11 points, partner») and hope by entering the auction later to confuse everybody.
The merit of four spades is that it puts maximum pressure on the opponents, especially since at this vulnerability they have to consider bidding as a sacrifice as well as to make, so that if one of them does enter the auction his partner will be unsure how much leeway to give.
The demerit of four spades is that it may go for a large penalty when the opponents can’t make anything.
The merit of one spade is that if partner is strong, you will be able to investigate the hand thoroughly and if partner is weak, you will stay out of shark-infested waters.
The demerit of one spade is that partner will place you with more defensive values than you have, and if the enemy start bidding he may start doubling.
Enough theory – what happened in practice? Well, this deal decided the fate of an important tournament in Turkey when the full hand was:
There was a single IMP between the teams when this deal appeared late in the match, and the North players chose different mainstream actions.
Where North opened 1, it allowed the opponents into the auction – but that worked out well for the opening bidder. South responded 1NT, West bid 2, North jumped to 3, East bid 4, South bid 4, West bid 5, and after two passes South doubled to conclude.
North must have wondered if this was one of the deals above where his lack of defensive values meant that his partner’s double would present the opponents with a few more points. But he had enough defence – K and his Q proved crucial, and the final contract went one down.
At the other table North chose 4, passed round to West who doubled for takeout. All passed, and that contract was also one down.