I scored a rare win playing last week in a Wanderers friendly with Martin Bateman. We got a few things right, including a somewhat fortunate 6NT, but the hand that we discussed most was this one below.
I'm East (dkham). Once partner is a passed hand I've a bit of leeway and tried making a weak 3♦ overcall, with a hand that is a bit too strong with too few Diamonds. Straight after I regretted both not bidding 2♦ and not bidding 4♦, which probably means 3♦ was about right. My partner, who is much craftier than me, delayed giving support until the five level, which had the effect of pushing them to an impossible contract. So far, so good.
Against 5♠ partner lead a Diamond, ruffed in dummy. Declarer (Ted) immediately lead a Club from dummy. Partner won his Ace, but was not to know that I had a singleton. He played another Diamond for dummy to ruff. Declarer won and lead the ♠J from dummy. It was crunch time. Should I cover with my King? At the time I thought that either (a) it didn't matter or (b) partner had ♠Txx in which case covering saves a trick. I didn't consider (c) partner had ♠QT.
You can see that I did cover, which reduced our trump tricks to one, and let the contract through. Apart from just finding the ♠J play, Ted also did well to duck my ♠K, as if he lets it run round to West's ♠Q he might still return a Club for me to ruff.
I can't see any legitimate layout where declarer can make it (unless trumps are 4-1 but then I think you're probably down anyway), so well done to declarer!
Despite this missed opportunity we won the first half of the match 42-20, and lost the second half 27-32 for a narrow win overall.