Declarer took the opening heart lead with the Q in dummy, making a right guess that should have saved his contract if he'd done just a little counting. He has two heart winners, three spades and three diamonds. That's eight. So he doesn't need six club winners, which in fact would mean a redundant winner, nor indeed does he need five. But he sure does need four. Now, make no mistake about it. The hand is a bit tricky from the standpoint of entries. He could spare a spade lead with that singleton since that wouldn't uncover the suit and he'd still have a lot of access to the closed hand. But still worse, there's only one entry to dummy outside of clubs. So he can't lead low to the 10 of clubs, figuring that after the defense hops on that trick, he'll have four club winners, since East can duck with impunity and declarer now has only 3 club winners. Similarly with coming to the A of spades and finessing the 10. If East ducks, declarer has only three club winners. There is indeed no alternative to banking on clubs being no worse than 4-2, hence:
Come to the A of spades, lead the 10 of clubs, overtaking with the J. If
East wins, declarer now has access to the remaining clubs, and when they split 4-2, has his contract. If East holds off, declarer is in dummy, and by the same token, he cashes the A and K, then concedes a club to East's Q and claims.
Yes, we note that because of luck with the diamonds, where he has four winners coming, and that opening lead, declarer could live with three club winners -- provided he hasn't sluffed a diamond on one of dummy's clubs! But he could hardly anticipate that luck nor should he count on it when the high probability of "no worse than 4-2" clubs would bring him home.
Anyway, declarer came to the A of spades at trick 2 and finessed the 10 of clubs -- into the queen! The two sides traded mistakes! Declarer offered East a chance to hold him to three club winners, to be overcome only by exceptional luck in diamonds and not sluffing a diamond on three club leads, while East declined to give declarer all that trouble in taking his Q, looking at A K J 9 in dummy. Declarer was practically on claim here with all top cards: four clubs, three diamonds, three spades and two hearts. Declarer could hardly have had his eye on four diamond winners, but that still leaves 13 "winners", which is to say, declarer already has a redundant winner. So how did he manage to parlay that holding into 11 winners?
Well, here 'tis: A heart to the A from East. Declarer cashes his remaining two spade honors, sluffing two hearts. Okay. He now goes to dummy with a diamond and cashes three top clubs, sluffing a diamond, a heart and a spade. Okay, though I'd be a little uncomfortable, since declarer is saving the 10 of spades, which he knows can't be a winner and pitches the 9 of diamonds which might be. But why think about diamonds when declarer has two more club winners, eh? But you know what's coming: declarer abandoned his remaining clubs, even though the suit had been led four times and worse, a return to the closed hand would mean he's saddled with a spade loser. But that's the way it was.
Case 2: Opening club lead to the ace. Now why wouldn't declarer finesse that lead, given that it might win and he's got only one entry to dummy and not least, that's his longest suit, for God's sake and he can afford one loser? Makes no sense. But worse comes at trick 2: Declarer comes to the A of hearts. Why would he uncover the one suit where he lacks second round control. Makes no sense, and I don't believe he could have made the contract with any luck at that point. Declarer has to lose a club to set that suit up and a heart lead would then spell his defeat. This one went down two and isn't worth pursuing further.
Case 3: This one was played from the other side of the table, and my first thought on seeing that layout was that a heart lead beats it. You've gotta duck it, and then you can't set up clubs. But wait! It was then that I noted the extraordinary luck in diamonds. That plus the 3-3 heart split will do it, for in losing a heart trick, declarer also gains access to 3 heart winners! Four diamonds, three hearts, three spades and two clubs will do it, as rather amazingly that powerful club suit brings in the least number of tricks of any suit. But this declarer didn't even have to bank on that, for he got a club opening lead from East's Q 8 7 5! Riding around into declarer's A K J. Talk about favors. Now let's see. We can certainly afford one more club trick (sluffing a heart) to ascertain whether the split's worse than 4-2 or not and find that it isn't. Well, let's cash one more club, sluffing a spade, and we find that we're not going to pick up that queen, but that a fourth club lead would leave us sitting pretty with five club winners, etc. So how did this declarer go down -- two?
Oh, oh, oh! I just saw that declarer's first mistake was to let the 10 of clubs hold the trick in dummy! (Playing from the North hand, please remember). Oh, good heavens! I didn't even picture that. No, with only one entry to dummy, declarer can't establish the club suit. Talk about trading mistakes! Anyway, declarer now came to his closed hand with a diamond and cashed his A, K of clubs, then continued into the fourth round, giving up the club trick he might have thought about doing earlier when he had an entry to his closed hand. A heart return was ducked, won by third hand. That was trick 6 and the declarer who got the most favorable lead was down already. You go figure.