Here are 3 eight card combinations. In order to maximize your chances for taking 4 tricks in the suit, the hands each must be played a different way. In the first example you have the J1098, all great middle cards. In the second, you have just the J10. In the third you have just the J9. This is a very practical exercise since 8 card suits are very common. Can you play each combination of cards to maximize your chances? Assume entries are not a problem. My suggested answers are below. If you have a better answer, let me know.
Hand 1: Declarer should start by playing the Jack from his hand. If West covers with the Queen the job is done. If West doesn’t cover, let the Jack ride anyway. The chance of a successful finesse is 50% and the chance of finding the Queen either single or double with East is only 16%.
Now place your self in West’s seat holding Qx. Do you cover on the lead of the Jack? I had this problem last Friday. I reasoned that if South had the 10 to back up the Jack, then he was going to finesse and we were not going to get a trick in the suit. On the other hand, if South did not have the 10, the only way we could get a trick was if partner held 10xx and I covered the Jack. Covering is correct only if you can promote a trick in partner’s hand. In this case I had everything to gain and nothing to lose by the cover. Unlike our example, declarer did not have the 10; he was hoping I would duck so he could smother the 10xx in partner’s hand.
Hand 2: The difference from hand 1 is that declarer does not have the 9. Here declarer should play small from his hand to the King (protecting against a single Queen in either hand) and then play small from dummy to his hand finessing the Jack if East does not play the Queen. Playing the hand in this order would guarantee you all the tricks if West holds the Queen single or if East holds the Queen and the split is not 5-0.
Hand 3: Here you are missing the 10. Go to the dummy with an outside entry and lead small to the hand putting in the Jack if East does not produce the Queen. If the Queen is West you are always going to lose it, but by inserting the Jack you guarantee that you will to lose to 10x or 10xx in the West. To win all the tricks you need the finesse of the Queen to work (50%) and the suit to split 3-2 (66%), so the odds of both being successful is .66 x. 50 or 33%.