LEARNING CENTER

If you cover the first honor and declarer has the ace and partner the 10, can you see that it will give declarer 3 tricks? It goes Q-K-A and then a finesse to the 9 in dummy. If you play low, and then cover the next honor partner gets his 10. If declarer has A10x, nothing you do will matter.

Covering the first honor is wrong. Picture declarer with Axx. He wins the ace and then leads up to dummy's 10 to get a 2nd trick. If you don't cover, the jack runs to partner's queen and you later cover the 10 if it is led. If declarer has AQx or even A9x, nothing you do will matter.

You have two honors, so cover the first one. If you don't, declarer gets an undeserved trick if he has, say, Axx. 

Declarer wouldn't lead the queen without the jack (would you?), so assume he has QJ and wait to cover until you see the second honor (picture declarer with QJ9).

Covering the J serves no purpose, so play low (hopefully without fumbling or thinking).

K. Cover a bare honor with an honor. Imagine declarer with AJ95. If you play the K partner will get the 10 eventually. If you play low, declarer will take all of the tricks in the suit.

1. There's a temptation to play the 10, but no reason for it. Declarer isn't likely to lead low to the 9 from AK9x. Imagine that declarer is going to play the A and K from AK74-playing the 10 promotes a trick for declarer. If declarer has AK95, playing the 10 won't help either as long as declarer has an entry to dummy. (If you think it important to give count and you play standard count, you could play the 6).