Hands are from Adventures in Bridge, October 20, 2018.
East: ♠8 ♥J8762 ♦KQ106 ♣AK4
West: ♠Q973 ♥5 ♦AJ542 ♣Q98
North opens 1♠ and East doubles for takeout. It is MUCH better to double with the East hand than overcall 2♥. You have excellent diamonds and perfectly respectable clubs if partner bids either suit, and you certainly would prefer a minor suit lead to a heart lead. Overcalling 2♥ with that awful suit is just asking for trouble.
South passes and West bids 2♦. North rebids 2♠. With a diamond fit and a singleton spade, the East hand is now a 6-loser hand, and so you has a perfectly reasonable raise to 3♦ opposite a partner who showed 0-8 HCP and four diamonds. South competes raises to 3♠.
West should be very happy to bid 4♦ for several reasons: (1) partner is marked for a singleton or a void in spades on this auction [visualization!]; (2) you have a singleton heart, so the two of you have NO MORE than two losers in the major suits; (3) you have a fifth diamond. Partner must have four diamonds for her raise of your earlier bid, so you can see a lovely cross ruff developing between your two hands.
If the opponents push on to 4♠, you will double for penalty. You know they are (probably) in a 6-2 fit and your ♠Q973 will be of great nuisance value, particularly as you expect diamonds to be a “tap suit.” When you force Declarer to ruff enough times in the long-trump hand, the “tap”, you eventually end up with more trumps than she has, and she loses control of the hand.
Though 4♠ can only be set one, the opponents are vulnerable, and +200 would be an 75% board. If you don’t double, +100 will be only a 32% board, losing to diamond partscores your way and the diamond game, which was bid by 2 out of 15 E-W pairs, and works on your 21 HCP combined because you have the “magic fit” hands.
South (Dummy): ♠KJ43 ♥J1064 ♦1086 ♣93
East: ♠98 ♥97532 ♦KJ92 ♣64
Partner (West) opened 1♣ and North overcalled 1♠. As East, you passed. South raised to 2♠ and West rebid 3♣. North’s 4♠ end the auction.
You led the ♣6. Partner took the ♣A (denying the ♣K which is obviously in Declarer's hand). Partner then cashed the ♥K (lead the King from AK in the middle of the hand even if you lead Ace from AK on the opening lead). Declarer’s ♥Q fell, and you played a discouraging heart. Partner switched back to the ♣Q.
Declarer took the ♣K and played one top spade, and then a second round of spades, winning in Dummy. You followed, but partner showed out on the second round of spades. Declarer then played the ♥J from Dummy. Your partner covered with the ♥A, and Declarer ruffed. After a third round of spades to Dummy, Declarer discarded a diamond on the good ♥10. Declarer then ruffed Dummy's last heart.
Declarer played the ♦A and another diamond. On the second round of diamonds, you can play the ♦K or the ♦J to win (with the ♦10 showing in Dummy). If you are not paying attention, or if you lost the count of the hand, as did I, you play the ♦J and endplay your partner. She will be stuck winning the trick with the doubleton the ♦Q and have nothing but clubs left to lead—providing a ruff-and-sluff for Declarer to discard another losing diamond.
You must rise with the ♦K—a Crocodile Coup—to “swallow up” your partner's doubleton Queen and be able to cash your ♦J. My apologies to Kathy Moyer for missing my chance to be a heroine.
The full hand, rotated to make declarer South, was: