On this deal from online play, try taking the East cards:

LHO opens 1, partner passes and RHO bids 1NT (announced as semi-forcing). After your pass, LHO jumps to 4 and buys it there. Partner leads the 6 and you see:

Vul:E-W Dir: South	J32  54  J543  KQJ9
		9875 92  1098  A854

Declarer wins your 9 with the 10 and plays a low club to dummy's king.

What are your thoughts?

For one, you need to know when to take your A. Two, you will need to know what to do after you win the A.

Do you win the first club?

Oh, you want to know which club partner played? Good idea. In this situation, count is crucial. In general, count signals are given when declarer leads a suit. Partner's club was the 2. Assuming standard signals, that means he has an odd number of clubs. When dummy plays the king, what do you do? Partner would have led a singleton club (not to mention that declarer would have drawn trump if he had four clubs), so you know partner started with three clubs. That means declarer started with two, so you duck this trick. Declarer continues with the Q. Now, you win your club ace, but what next?

Oh, you want to know again what partner played? Another good idea. Most defenders just turn over the trick and don't notice. Your partner had two clubs to choose from on the second round. There is no need to give count again. Attitude is not relevant (you know his club holding). This is where good defenders use suit preference. Since you must know, partner played his lowest remaining club.

Accordingly, you should play a diamond. This was the Real Deal:

Vul:E-W Dlr: South	J32  54  J543  KQJ9
A104 876  AQ72  1072		9875 92  1098  A854
	KQ6  AKQJ103  K6  63

East's defense of winning the second club and shifting to diamonds allowed West to take the setting tricks.

After winning the trump lead, why didn't declarer continue to draw trump? Because that would have given the defense more chances to signal. West could play his trumps to indicate what suit he likes (in fact, many pairs would have already shown suit preference by the size of the trump led at trick one). Also, the defense would get a chance to discard if declarer were to draw trumps.

Still, when clubs were played, West's count signal followed by a suit preference signal paved the way. If East plays a spade upon winning the A what happens? Declarer plays the K. If partner wins, the J becomes a dummy entry. If he ducks, declarer draws trumps and plays the Q. Again partner must duck, but now another spade puts partner in and the best he can do is cash the A to hold it to 10 tricks.