Hands are from Adventures in Bridge on September 12, 2018.
East: ♠A8753 ♥AKQ4 ♦10 ♣K96
West: ♠Q2 ♥872 ♦AK9875 ♣A2
You become Declarer in the West seat after partner opens 1♠ and rebids 2♥ over your 2♦ response. The opening lead is the ♣3.
When developing long suits, in no trump and in suit contracts, it is vital to consider the entries to the hand with the long suit you wish to develop. Our Declarer did not remember that essential principle and played a low club from Dummy. My ♣J forced his ♣A. He went to Dummy with the heart and played the ♦10, overtaking with the ♦A, the played the ♦K, and gave up a diamond, finding them 3-3. However, he is now cut off from his hand. If North returns a heart or a club, Declarer will be stuck on Dummy and can only come to eight tricks: one spade; three hearts; two diamonds; and two clubs.
Incidentally, after the helpless declarer cashes his winners, South must be careful to lead the ♠J from her ♠J10 doubleton when she wins the third round of club—rather than returning another club and end playing partner in to leading away from his ♠Kx, giving declarer the contract despite his poor play.
Declarer can easily take 11 tricks if he wins the first club on Dummy with the ♣K (trick one) and then plays the ♦10, letting it ride—lose your losers early.
South: ♠A97 ♥7 ♦AKJ8762 ♣J9
North: ♠K82 ♥AQ109 ♦10 ♣A7642
Partner (South) opens 1♦ and RHO doubles for takeout. Your correct bid is redouble with the North hand. This implies a misfit hand and shows 10 or more HCPs. A 2♣ bid is NOT forcing. Partner can pass. After an opponent makes a take-out double, the most common treatment is that bids at the one level are one-round forcing because you don't want to risk missing your 4-4 major fit by failing to mention a major when you can. Bids at the two level are weak and not forcing. Partnerships should discuss and check the appropriate box(es) for New Suit Forcing under the section OVER OPP'S T/O DOUBLE on their convention card.
Alas, North actually bid 2♣ and South rebid 2♦. North then bid 2NT (which is NOT forcing)—North mistakenly thinking that two over one game force applies after a take-out double by opponents. [It does NOT. There is no 2/1 game force in any competitive auction.] South then bid 3♦. The 3♦ bid says: “I have a weak hand, with a long suit. Do not bid 3NT without a filling honor in my suit or you may be sorry.” [Remember, South thinks that North has a non-forcing hand.] North bid 3NT ending the auction.
The lead was the ♥3 (fourth-best leads). Just like Hand #5, Declarer has the singleton the ♦10 opposite a long suit. Furthermore, Dummy (the hand with the long suit), has only ONE outside entry. So, proper play is to kill the ♥K (which is played by West) with your Ace and put the ♦10 on the table. When East play low, you must overtake the ♦10 with the ♦J or ♦Q. You will not get enough diamond tricks unless diamonds are 3-2, so you must assume a 3-2 diamond break and therefore not don't worry about a 4-1 diamond break. East (your LHO) is likely to have the ♦K, and West (the take-out doubler) is likely to have all the other high cards. When the ♦Q (or ♦J) of diamonds wins, you cash the ♦A. Both opponents follow to the second round of diamonds, so you simply give up a diamond and still have the ♠A to get back to Dummy. Now you take six diamond tricks, two hearts, two spades, and one club. If you let the ♦10 ride at trick two, from misplaced thriftiness, best defense can limit you to eight tricks.