Keep the road clear of a blockage

Roberto Azevedo, a Brazilian diplomat and the current director-general of the World Trade Organization, said, "Each blockage is a blockage. Each impasse is an impasse. You have to find a solution; there is no recipe that fits each one of them."

Blockages can be dangerous in bridge. If it is, say, declarer's singleton ace opposite dummy's king-queen-jack, usually declarer should cash his ace as quickly as possible, then work out how to reach the dummy to cash those winners.

Other blockages are less easy to anticipate. In this deal, how should South play in three no-trump after West leads the spade king?