There is always an element of magic about a trump promotion, a kind of conjuring up of something out of nothing. Even low cards seem willing to take on the role of a David versus the Goliath, represented by declarer's much greater trump strength. Trump promotions are always particularly satisfying when they involve an element of persistence: this was a nice example, playing against Catherine Curtis and Jon Cooke.
The bidding was instructive.
West North East South
1NT(1) 2♦(2) Pass 2♥(3)
(1) 12-14 balanced
(2) Showing spades plus another longer suit (this is called "anchoring to the short-suit")
(3) Looking for a fit and showing better hearts than spades
West had a slightly tricky opening lead. Having a good holding in dummy's known side suit together with trump control, it might not be unreasonable to start with a low trump in the hope of reducing chances of a cross-ruff. As for leading a top spade, it is always with trepidation that one leads dummy's side suit at trick one since this may also aid declarer's task of setting up the suit. Taking the other options in turn, a diamond lead would be leading into declarer's presumed strength and while there maybe a club ruff to be taken, playing duplicate pairs there is little incentive to make the "heroic" lead of ♣K.
After due deliberation, West led the ♠A and saw partner's high-for-hate ♠9. Looking at dummy, a club and a diamond were clearly unappealing continuations, thus suggesting the winning defence almost by default. ♠K followed (notionally establishing dummy's spade suit) and then a third spade (on which declarer had no useful discard).
Declarer now led a trump from table to the queen and West's ♥A. A fourth round of spades duly followed. Dummy's ♠J was ruffed by West with his last trump and hey presto, a second trump trick had appeared for the defence. Although declarer could over ruff with ♥J, West was now sure to make a trump trick with his ♥10.
Declarer was not quite out of the woods for dummy still had a potential club loser. However South knew from the bidding that West, having already shown up with eleven points, could not also hold ♦A. There was therefore no need to take the club finesse (which might be losing). Instead she led the ♦K and East was effectively end-played after winning the trick - forced either to return a diamond to declarer's winning ♦Q, (allowing a club pitch from dummy) or play a club into the ♣AQ on table. Of course, if East had held a third heart, East could have played that, but then declarer would not have had a trump loser.