East discouraged with the club five but West continued with the king. East contributed the ten as a suit preference signal asking for a spade shift. Partner complied by shifting to the deuce of spades for the queen and king, ensuring the defense of their quota of three tricks, N-S +420.
If West fails to return a spade at trick three, declarer will dispose of a spade on the jack of clubs to bring home an overtrick.
North responded 1NT because Flannery was in their bidding toolkit. South would not hold four spades unless he was strong enough to reverse (17+ HCP) and the spade fit would be uncovered in this scenario.
South rejected a two diamond rebid preferring instead to focus on the six-card heart suit. North, rather questionably, opted to boost to the major suit game. His hand was comprised of quacks but the contract could not be defeated on this occasion.
3NT might be held to nine tricks since the defense owns four black suit winners.
East might start with the ten of clubs where West must be careful not to play three rounds of the suit or North will record eleven tricks. Questions on bridge can be sent with a stamped, self-addressed envelope to The New Canadian Bridge c/o Torstar Syndication Services, One Yonge St., Toronto, M5E 1E6.