LEARNING CENTER

Pass. Even if playing penalty doubles, you have nowhere near enough.

A. A normal 3rd-hand high situation. Putting in the 9 makes no sense here and just allows declarer to win the trick cheaply.

K. From the heart spots, you can tell partner has led from only a 4-card suit (there are no other hearts below the 5).
If you return a normal 9 and partner wins (declarer covering it), partner won't have any clue what to do next. He might not be able to play more hearts from his side. 

By playing the K (ace from ace-king is only at trick one), he will know "where you live." He will know he can get back to you in diamonds. These are the remaining cards:

If you play the 9 to the 10 and jack, partner isn't likely to guess to play a diamond--declarer will easily make the contract. With your helpful K and then 9, partner will win the 10 with the jack and play another diamond. The defense will take the first 7 tricks for down 1. This is the full deal:

Thank you for playing the 4 practice deals on "Over My Shoulder Defense" (Part 4 of 6)."