The first decision point comes after three rounds of trumps, and you cash the
♠Q. If North shows out, South is either 7=1=1=4, 7=2=0-4, or 7=0=2=4. How this works in these ending and how it relates to the other plays is shown in the two hand diagrams.
If he is 7=1=1=4 or 7=0=2-4. He can not protect North from a red suit squeeze, If he is 7114 and exits a heart, win the ace, cash spade king, cross to king of diamonds and finish the trumps. If he exits a diamond, use a trump squeeze. Win the Ace in hand, cash one trump, setting up a trump squeeze (criss-cross basically). CAREFUL.. cross to dummy in diamonds (you need entry to hand opposite the trump in the threat suit in the hand in the trump suit... that is the criss-cross nature of the trump squeeze). Then cash the
♠King. That does East in.
If he is 7=0=2=4, you can play the same line with the same trump to trick 6 (after cashing
♠Q and learning of the 7=1 spade split).
If South is 6=1=2=4, again the cash the
♠Q and throw him in with a trump leads to the same two squeeze options regardless of his exit (heart, diamond, or spade). This is because he can not stop either red suit. ..as well as if he is 6=2=1=4 with
♥62
If he is 6=0=3=4 you will set up diamonds on he same line easy enough as the heart ace remains in dummy. You will think you are squeezing North in the reds, but when you eventually ruff a
♦ they will be good and you will have the heart reentry.
That leaves us with the dreaded 7=2=0=4, 6=2=1=4 and 6=3=0=4. The good news is you can not come up with a hand where South will have three hearts and North will throw away the
♥K. (Surely he would have at least
♥KQJ for a discard of a heart and no one would throw one from just KQJ as heart ace and a might set the hearts it sounds like declarer may have for his takeout double, losing jus tone).
So we have 7=2=0=4 and 6=2=1=4 as the possible distributions. I can't see any reason why North would not hold on to his
♥Tx (his three choices are
♥T6
♥T2 or
♥62, as are sure North started with
♥KQJ+1 more at least. So there is a 1/3 chance when South has two hearts, they will both be small. So I would play the same way, hoping if West has the
♥T2 or
♥T6 he leads the
♥T to "help" his partner locate the high hearts. No other play works, as South will clearly hold onto this
♥Tx and North can see the diamonds so he has to keep those.