These three hands are from Adventures in Bridge, September 15, 2018.
South: ♠3 ♥AK632 ♦K8 ♣AK852
North: ♠AKQ ♥54 ♦Q75 ♣Q10976
The bidding on this hand was wild. North opened 1♣ and South bid 1♥. North rebid 1NT and South rebid 2♦—New Minor Forcing, showing five or more hearts and at least invitational values. West, holding the ♦AJ109 of diamonds, doubled for the diamond lead—a dangerous bid with only four cards in the suit. North passed and East (with 2 HCPs) bid 2♠ on his ♠J9854 of spades. I would have liked to declare 6♣ or 6NT from my (South) side of the table, but that was now impossible as partner had bid both clubs and NT before me. So, I simply bid 3NT. Partner is likely to have a diamond card on this auction and I wasn't about to bid 5♣.
The lead was a diamond and partner called for dummy's ♦K. West took the ♦A and returned the ♦J. Partner played too quickly, and ducked this round. Even though a squeeze looks unlikely, it costs nothing to take the second round of diamonds. You know you have five club tricks; three spade tricks, two heart tricks, and one diamond trick, one short of the trick you might gain from a squeeze, i.e. the count is rectified if a squeeze exists. Since West holds the ♥QJ98 of hearts AND the ♦AJ109 of diamonds, declarer's ♦7 is a diamond threat and Dummy's ♥6 is a heart threat. When North runs all the black suit winners, West will have to abandon one of the red suits, and a 12th trick magically appears.
This is a very lucky squeeze because the red menaces were both small cards. Even if West had had a five card suit for his lead directing double, East could easy have started with ♦10xx or ♦9xx, and East's heart holding is lucky too. But overtricks are worth a lot in matchpoints; every opportunity should be explored.
North: ♠6 ♥AKQ7 ♦1072 ♣AKQJ3
South: ♠K10852 ♥J10864 ♦— ♣965
South passed as did West. North opened 1♣ and East overcalled 1♦. South bid 1♠. (A negative double would not sound like a 5-5 hand to partner). West raised partner to 2♦ and North bid 2♥. East passed, and I (South) jumped to 4♦ with the South hand, a splinter bid promising four card heart support and a singleton or void in diamonds. Partner has reversed, promising at least five clubs and at least four hearts, along with 17 or more HCP. He is unlikely to have anything in diamonds, so my void is worth at least 5 HCPs with our known 9-card fit. Partner bid 6♥ which makes easily, losing only a spade trick.
North: ♠A9732 ♥62 ♦KQ63 ♣J6
South: ♠5 ♥AKQJ83 ♦52 ♣AK92
I (South) opened 1♥. West passed. Partner bid 1♠ and RHO (East) overcalled 2♣. I jumped to 4♥ which ended the auction.
LHO led the ♣4. I carefully played the ♣6 from Dummy, trying to look like someone who may not have any other honors. East put in the ♣10, which I won with the ♣A. Now East does not know whether I have the ♣K or whether her partner has led from ♣K94. Since I was aiming for a swindle play, I immediately led a diamond to cut communication between the partners. I'm expecting that RHO will want to attack the ♠A entry in Dummy and sure enough she win the trick and returns the ♠K. I take ♠A and run off five rounds of hearts to put the pressure on.
East is feeling under the gun. She started with ♠KQ10 ♥105 ♦AJ ♣Q108753. She does not want to let go of a diamond, because I might own the ten. She does not want to give up a spade, because she is unsure of the position, so she ends up discarding three clubs. Now I play a diamond to the ♦Q. I play the ♣J from Dummy; East covers with the ♣Q. I cash my good the ♣9 and take the twelfth trick with the ♣2.
I actually took a risk going for the swindle play. If East returns a club when she is in with the ♦A, I can now be held to ten tricks. Playing straight up, due to the club spots, I can always make eleven tricks just by pulling trump immediately, giving up a diamond, and finessing again in clubs.