You and your partner manage to get to a dicey 6♦ after you showed a strong red two-suiter. West leads the ♠3, fourth best. Plan the play. (Trumps are not 4–0.)
Your best shot is to win the ♠A, cross to a diamond and lead the ♥J to the king, a heart to the ace, and if the queen hasn’t appeared, ruff a heart.
Assuming hearts are 3–3, return to your hand with a trump (you also need trumps 2–2), discard dummy’s spades on winning hearts, ruff your spade loser in dummy, and chalk up your slam. If the ♥Q makes an early appearance under the AK, draw trumps and claim.
The trap is not to draw two rounds of trumps before ruffing a heart. If you do and trumps are 2–2 or 3–1, you can no longer afford to ruff a heart because even if hearts are 3–3, you can’t get back to your hand to run the hearts to discard spades other than with dummy’s last trump, a play you cannot afford.
If you draw two rounds of trumps and they are 2–2, take the heart finesse one way or the other hoping the player you play for the queen has ♥Q x or ♥Q x x. It is a tiny bit better to play East for the ♥Q rather than West. If you play West for the queen and run the jack, you could lose to a stiff queen in the East hand.
If diamonds are 3–1, you need to take the heart finesse one way or the other. If you decide to play West for the ♥Q, run the jack, cross to the ♥K, return to your hand with a trump and hope the ♥A drops the queen. If you decide to play East for the ♥Q, it is safe to draw a third trump followed by the ♥K and a heart to the jack. On a good day, East will have the queen with fewer than four hearts. Drawing two rounds of diamonds early is not as good percentage-wise as the recommended line. (Approximately 34% to 28%.)
West leads the ♠2 (low from strength). East plays the ♠J. Plan the play.
Win the opening lead: You can’t stand a club shift, and besides, spades figure to be 4–3. If West had five spades headed by the K–10–9–8, or five spades headed by the K–Q–10–8 or five or six spades headed by the K–Q–10–9, the 2 would not have been led.
Cash the ♥A Q, duck a diamond, and let them take their three spade tricks. Once their fun and games are over, you have nine tricks unless diamonds were 5–0 and hearts 4–2. Your ducking play saves the day (and the $$$) when hearts are 4–2 and diamonds are 4–1.