This deal was played in 2018 in China during the World Youth Team championships. South held:

 AJ4  
 KQ103  
 92  
 KQ53.

His partner opened 1 and he responded 1, raised to 4. Some of my newer students mistakenly think of that as a "closeout" bid, but it is anything but. Opener is showing about 19-20 points in support. One young player now used RKC and opposite all the keycards and one king he (the optimism of youth) bid 7. A spade was led and he saw:

63  A942  AKQ7  AJ2

AJ4  KQ103  92  KQ53

What is the plan? If trumps are 3-2, the contract is a claim. Draw trump and throw a spade from dummy on declarer's 4th club. Dummy is now high (other than the 7 which gets trumped with declarer's 4th heart).

So, what if hearts aren't 3-2? This is such a common question, that it is the title of the article. How to handle a 4-1 break often requires deep thought and logic.

If the J drops singleton, things are easier, but what if an opponent has Jxxx? If it is West, declarer can lay down the KQ, getting the news and take a marked finesse against West's jack. If it is East with the Jxxx, the KQ will spell defeat, but the K and then A would reveal the break and allow for a marked finesse the other way. So, which shall it be?

That depends on the full plan for the deal. If indeed hearts are 4-1, where will declarer want to take a ruff? The only way to trump a spade in dummy would be to draw trump first and then run clubs. However, if trumps are 4-1, that won't work. On the other hand, a ruff in hand (of the 7) can be taken without having to draw trump first. Therein lies the answer.  Declarer should win the A and lay down the K. When everyone follows low, he should next play the Q. Why? If trumps are 3-2, he can claim (draw the last trump). But, if RHO shows out, he is still alive (if LHO shows out, he was never realistically making the contract--unless he had hand records). Next come the AK and the 7 trumped with the 10. If this lives, declarer now plays a heart to the 9 for the marked finesse and then the A to claim 13 tricks.

Confession, on the Real Deal, hearts were 3-2, but for my readers, this is the Real Deal to be concerned about:

Vul:North Dlr: Both	63  A942  AKQ7  AJ2
Q987  J865  J43  97		K1052 7  10865  10864
	AJ4  KQ103  92  KQ53