LEARNING CENTER

Yes, endplay either opponent. You have one heart loser and one potential club loser. Rather than try to guess clubs, after winning the first trick, draw trump. Now play all of your diamonds. After clearing that suit, play your remaining high heart and then exit with your losing heart. Whoever wins will have to either lead clubs or give you a ruff and a sluff.

Yes, endplay either opponent. Win the first trick and draw trump. Now cash your high diamonds and ruff a diamond. Note that we wouldn't normally like to ruff diamonds since this is ruffing in the hand with longer trump. Here, it helps us eliminate the diamonds. Now cash the remaining high heart and exit with your low heart. I hear some students thinking, "why bother?" Imagine the K and A to be in separate hands and clubs 4-3. Try to take any tricks in the suit when you have to lead it yourself.

No, can't eliminate other options. Once you don't have trump in both hands, the opponents can safely exit a red suit, forcing you to guess. Your best line is still to win the first trick, and draw trump. If trump had split 2-2, you could eliminate the diamonds and then play a heart to endplay either opponent (and guarantee your contract), but not here. You might still ruff out the third diamond to see if you gain any information about the shapes of the opponents' hands. After that, take your best guess in clubs. If both opponents follow to the diamonds, then the person with only one spade is more likely to have the missing Q since they have more vacant spaces (aka cards you don't know about). 

Yes, endplay West. You have one heart loser and two potential spade losers. If the diamonds were 3-3, you would pitch your heart from your hand and play a spade to the king for a potential overtrick. Since diamonds didn't behave today, you have no way to get rid of the heart loser. The key here is the J. If you play hearts, you know that West (who led the K from KQ) will win and have to play either a heart giving you a ruff and a sluff or a spade into the opportunity holding: the K752. Since West only held 2 diamonds, you don't need to ruff the 4th diamond first, but it can't hurt.

Yes, endplay either opponent. You need to think ahead for this, however. Win trick one with the ace of clubs, and ruff a club at trick two with the ace of spades. Now play your 7 to dummy and ruff the third club. You can draw the remaining trump and play three rounds of hearts, forcing either opponent to play a diamond or give up a ruff and a sluff. If you tried drawing trump first, you can't eliminate the club suit.

No, can't lose to the correct opponent. Here, the opponent you'd like to lead clubs is West, which would guarantee your contract. Unfortunately, you can't guarantee that West is going to be the one to eventually play clubs. Here, you should take the club finesse yourself, and if the finesse fails, fall back on hoping that clubs split 3-3. Note: At IMPs, K, A and then low to the jack (to guard against Qx with West) is sensible.

Yes, endplay West. This isn't really a traditional endplay, but I want you to think about having the right opponent on lead. We don't have one opportunity suit here, but four. For this "endplay", we don't have to eliminate suits, but just let West win the first trick. If West continues spades, we will take two spade tricks. If West switches to a heart, diamond, or club we can set up tricks in diamonds while maintaining control of the spade suit.