[RunemPard]

Matchpoints...
Opponents were playing 4 card openings, variant of J2NT w/ and w/o interference...
We were sitting N/S...
The auction went...

East(Y) - South(O2) - West(P) - North(O1)
1♥ -------- 2♣ -------- 2N* ------- P
3♥* -------- P ------- 3♠* ------- P
4♦* ------- P -------- 4♥ -------- P
4N -------- P -------- 5♦ -------- P
6♥ -------- AP

*2N - Asking bid 10+
*3♥ - single ♣
*3♠ - control
*4♦ - control
0314 RKC

A of ♣ is led by SOUTH followed by another ♣...plan the play.

--------------------------WEST (DUMMY)
--------------------------♠Q
--------------------------♥K9843
--------------------------♦K43
--------------------------♣KJT2

SOUTH ----------------------------------------------------NORTH
(bid 2♣ and leads A) ---------------------------------(passed all rounds)

--------------------------EAST (DECLARER)
--------------------------♠AT42
--------------------------♥AQ72
--------------------------♦AQT7
--------------------------♣8

[billw55]

Let's see, I don't think I can pick up either 4-0 trump break (that pesky 7). Also if RHO ruffs trick 2 with the stiff 7, LHO gets a trump trick; but there is nothing I can do about that.

So this just looks like an ordinary dummy reversal, low from dummy at trick 2, draw trumps (which must be 3-1), and if a club loser remains, ruff it in hand.

edit: OP fixed the 7 so the above no longer applies. Now it is a matter of considering the 4-0 breaks.

[RunemPard]

to billw55 when you wish to read...

Spoiler

You just pointed out a major flaw in my thoughts. You are absolutely correct. I will adjust the 6/7 for the sake of this hand being playable, but as you just pointed out it is not with the 7 as it was.

[Quantumcat]

♣J, if it gets ruffed, over ruff. ♠A, ruff a spade, diamond to the ace, ruff a spade, heart to the ace (presumably seeing LHO show out), ruff a spade. King queen of hearts to finish them off. Return to dummy with ♦K and cash ♣K to discard losing diamond.

If club does not get ruffed: discard losing diamond. ♠A, ruff. ♥K (assume we find out 4-0 with RHO), 1st heart finesse. Spade ruff, 2nd heart finesse. Draw remaining trumps, go to dummy with ♦K, discard last spade on ♣K.

I think this works, I think we have enough trumps. Although please do correct me if wrong :-)

[RunemPard]

Quantum

Spoiler

Seems to work...many chose to ignore the possible 4-0 split and played the A or Q from hand first. I find SOUTH holding 4 hearts extremely unlikely, so best shot is to start with the K.