Opening leads against slams used to be a big Achilles Heel for me. I remember once in CNTC qualifying, Wayne doubled Glen and David T in 7NT and reached into his hand to grab a card.
Unfortunately it was not his lead. He had bid 2 suits. I chose the wrong one. Only about a 30 IMP swing (down 6 versus making 7.) Luckily we still won that match.
I had a couple of lead problems against slams in the 'crazy set' with Jeff. I got one right and I got one wrong. See if you do better or worse.
1st problem:
Uncontested, starting with Righty, who dealt:
1 Heart - 2NT - 3NT - 6 Hearts
I think it's safe to presume that 2NT was intended as Jacoby, but it was not alerted.
643 / 652 / AT86 / QT2
2nd problem:
Uncontested, starting with Lefty. You dealt:
1 Heart - 1 Spade - 2 Spades - 3 Clubs - 3 Diamonds - 4NT - 5 Hearts - 6 Spades
AT52 / 864 / K85 / QT8
First problem:
643 / 652 / AT86 / QT2
It seems like the normal lead is a Club. You hope that partner has the King and that you can set up a Club to go with your Diamond trick.
Alternatively, it's possible that a Diamond is right. This wasn't the most scientific auction in the world and maybe they're off 2 top Diamonds.
On the other hand, maybe a trump is right. If Lefty has 4 Hearts, as seems likely, you're definitely not pickling partner's trump holding. It's certainly possible to construct a hand where you've got to lead a trump here.
Sigh. A Club, a Diamond, or a Heart?
No.
Of course, a Spade is the only lead to beat it (twice, even.)
Second problem:
AT52 / 864 / K85 / QT8
In my younger days I'd whip 6 Spades in a heartbeat. Mostly because I expect to beat it, but probably on some level also to give Declarer a 'sporting chance.'
Of course the days of sporting chances are over. Avoiding looking foolish is the new goal (not always achieved, as my readers well know.)
It's possible that Righty psyched the 3 Club cuebid, but that didn't seem too likely once Lefty cuebid Diamonds. I hoped to score 2 tricks in the blacks and put pressure on Declarer at trick 1 by kicking off proceedings with a Diamond and making him guess whether to hook or not (the Ace is presumably in Dummy.)
I led the 5 of Diamonds and down he went.
KJ84 / KJT72 / AJ4 / 2