[han]

x
9xx
K107x
KQ107x

AKQxx
AQx
Q8
AJx

While our teammates defended 3NT, my partner and I bid 6C on these hands so a lot of IMPs are at stake. I'd like to ask how you would play the hand, but I am afraid I should give you our auction. South opened 2C in fourth seat (showing either a weak hand with diamonds or various strong hands), our auction continued:

2C* - 2D
2NT (22-23) - 3S (both minors)
3NT (no 4-card minor) - 4C (5+ clubs, 4+ diamonds)
4H (cue for clubs) - 4S (cue)
4NT - 5C
6C

After a very long pause LHO leads the 5 of diamonds. You play low from dummy and RHO plays the 9.

[Fluffy]

cash the 3 spades before playing a diamond, cross ruff your way to 12 tricks. To avoid LHO dicarding his third on a diamond at trick 3.

EDIT: Thinking deeper there is no need for that, for if RHO plays a low diamond at trick 3, we still have an entry to hand in hearts and 12 tricks are avaible just ruffing a spade in dummy. However if LHO ruffs ♠Q we are in time of plaing ♥ finese, so something is something.

[foobar]

How about a ♦ at T2/

It would be interesting to find out what their leads are (not that anyone leads honestly against slams anyway). I guess the long hesitation was debating whether to lead from K♥ into the balanced hand...

[han]

If you play a diamond at trick 2 RHO wins and plays a heart. Then you probably guess to go up with the ace and you are down.

If you play 3 rounds of spades immediately you see that LHO ruffs the third round. Then you know you need the heart finesse, which is onside.

Well done to Fluffy.