Here is an interesting defensive hand from a recent game. Put yourself in the East seat:
East
North opened the bidding two clubs. South responded two diamonds (waiting). North’s rebid was 2NT (22-23 HCP). Souith raised to 3NT. Finding the right defense was difficult. What would you lead from the East hand?
Time to count: You have 12 points, declarer has 22-23, dummy should have 3+, and partner will be lucky to have so much as one jack.
Knowing from the bidding that partner is probably broke and that opponents have shown no interest in the majors, East should consider a heart attack on opening lead. But which card? I recommend the king* of hearts. Partner will give you attitude when she follows suit. You lead the king, and this is what you see in dummy:
Dummy
When you see Dummy come down you realize that South got a bit too aggressive when she bid 3NT. It’s not a percentage contract, and there is hope for your side. You can now place Partner with two or three points. Partner plays the encouraging seven, and declarer follows with the six. Now what? Do you play the ace or lead the eight, hoping partner has the queen?
My take is that you should cash the ace. It’s more likely that declarer, rather than partner, holds the queen. Partner has no entries, and you may be able to drop the doubleton queen. If partner happens to hold the queen, nothing is lost.
*The recommended lead from A K J 9 is the ace, asking partner to play her highest card. That will let East know if the suit will run. But your heart holding isn’t good enough for that (8 rather than 9).