Solution

The only way to 100% guarantee this 3NT contract on the five of Hearts lead is to play the Jack of Hearts at trick one.

If the defenders now switch to a different suit at trick two, you immediately win the Ace and you can now afford to duck a Club, seeing that the defenders cannot cash five tricks.

However, I am sure that the defenders will continue the Heart suit.

Do not panic.

Just cross to dummy’s Ace of Clubs and lead the NINE of Hearts, so that you can discard that embarrassing NINE of Clubs.

The 5 of Hearts lead at trick 1 means that the defenders can only cash 4 Heart tricks.

Once the defenders have cashed their 4 Heart tricks, you can claim the rest of the tricks, seeing that you have discarded the 9 of Clubs on the 9 of Hearts.

Thank you to Marc Chawner