With South most likely holding the ♠K and ♣A, West played best for nine tricks.  If West ducks the spade lead, there is a risk of a heart switch.  Leading a club to the queen at trick 2 guaranteed nine trick if South holds the ♣A and ♠K, while likely, not guaranteed.  At the table most would duck the opening lead and take their chances with a heart shift, which may or may not be critical.  South ducks the club lead at trick 2 and declarer crossed to dummy in diamonds and leads toward the spade Q.  Five diamonds, two spades, one club and one heart.  Well played!

Jack was consistent in opening a suit with 5-4-2-2 and 16 hcp.

An easy 4♥

With less information than at table 1, Q-Plus Bridge went down in 3NT when it played the ♣ K at trick 2 (leading toward the ♣K does no better, but is a better play) and South switched to a heart at trick 3.  Declarer miss timed the play and went down one.

Table 1 EW 3NT +400

Jack +10 IMPs

With a 4-3-3-3 hand, East reasonably bid 3NT rather than looking for a 4-4 heart fit.

Table 1 EW 4♥ +620

Jack + 12 IMPs