Marchpoints, neither vul.
Partner passed originally. He also did not employ the Drury convention (check it out if you do not know it, it is a useful tool to keep from getting too high when you open light in third or fourth seat). Therefore you probably do not have a slam.
Your hand has 17 HCP. If partner has only 6 HCP, you only have 23. Nevertheless you should always bid game with this hand. Aces are underrated in the 4321 point count and you also have a nine-card spade fit.
You bid 4♠, all pass. The lead is the ♥J and dummy hits....
You want to discard a heart loser on the ♦K, but they have knocked out your entry to the ♦K, you can't unblock the ♦A now and get back for a discard.
What can you do to compensate?
If you draw trumps right away you will be stuck in your hand if trumps don't split.
If you take a club finesse, you can then ruff a club back to dummy. Therefore you win the ♥A and run the ♣J.....
Disaster! West wins the ♣K. and plays a heart to East's ♥KQ. Then they lead a fourth heart and they get a trump trick.
You lose the ♣K, ♥KQ, and a spade trick for down 1.
Can you do better?
One of the essential elements of declarer play is the holdup play. A holdup play is designed to exhaust a defender of cards in a suit, so that if he gets in, they can't lead that suit to their partner's winners.
Holdup plays are more common in notrump contracts, but this hand illustrates the holdup play in a suit contract.
So, instead of winning trick 1 with the ♥A, you duck! Now they continue the suit and you win the ♥A. Now you take the club finesse as before, and lo and behold West has no more hearts to lead!
Here's how the play might go:
Trumping your ace is a nice touch, too.
When I showed this hand to my student, she took the ♥A at trick one and went down. She said she considered a holdup but she was afraid of them ruffing the heart.
Okay, let's go there.....
Suppose the ♥J is a singleton. If you play low, East has to be aware enough to overtake the ♥J with an honor. Then, if he gives West a ruff, he ruffs your other heart loser with a natural spade trick!
The play would go:
When you are short of entries, look for a way to create more. On this hand, taking the club finesse followed by ruffing a good club is a way to get back to dummy.
A holdup play is a useful way to cut communications between the defenders' hands.
Plus... it's free!