Making Slams on Endplays are Just More Fun than a Simple Finesse

Last night turned out to be an interesting night at the bridge club. Here is one of my most interesting hands. First, it's a bidding problem, or rather, a question about what a particular sequence means.

The actual auction we had on the following hands was, with south dealer: 1NT-(2S)-2NT*-3C-4NT-6NT. 2NT was Lebensohl. What was 4NT? Playing Lebensohl, I reasoned that it should be quantitative with a spade stopper and that a jump to 4NT over 2S would be quantitative without a spade stopper. Of course, if I looked at my hand, I probably should have realized he can't really have a spade stopper since I had the AK. Anyway, I decided that any hand with clubs would have bid 3C over 2S, natural and forcing. And if he wanted to keycard in clubs, he would bid 3C and then 4C. Partner intended it as RKC for clubs.

6C is clearly cold with a diamond ruff providing the 12th trick but I was in 6NT, which is not a terrible contract either. How do you play to make it after west, who overcalled 2S leads a low spade and east contributes the J?

North
♠ T
♥ AJ8
♦ Kxx
♣ AKTxxx

South
♠ AK9x
♥ Txx
♦ AJ
♣ KQxx

You have 11 top tricks and 3 reasonable ways to get a 12th trick: D finesse, double H finesse, and endplay west to lead a spade into your K9 at the end. The diamond finesse is 50% a priori but given the overcall rates to be significantly less. The double heart hook a priori is 25% but probably more based on the bidding. You can play low to the 8, winning when west has K9 or Q9, or  you could play low toward the J winning when west has the K and Q. But if he has the KQ of hearts (or even just the K and doesn't unblock), you can make on an endplay by running the clubs, playing K-A of diamonds, then A and a heart. Needless to say, I took the latter line of play, which I do believe is the correct line of play. I'll make if west unguards his spades on the run of clubs or if west has KQ of hearts, or if west hold Kx of hearts and does not unblock. West had a beauty: Qxxxxx, QTx, xxx, x. I found the way to go down but I still believe it's the correct line of play.