[mtvesuvius]

V vs NV at IMPs, you hold:

♠JTx
♥Jxxx
♦T9x
♣KJx

You are silent, and witness this auction:

(1♥) - P - (1NT*) - P
(3♦) - P - (4♦) - P
(4NT) - P - (5♥**) - P
(6♦) - P - (P) - P

*Forcing
**2 Keycards w/o Q♦

[rogerclee]

♣x

Even if a spade is "right" in that it allows us to set up a trick, declarer may be able to pitch spades from dummy (dummy has at most 3) and ruff his losers in that suit anyway. I think a club is the best shot at beating it.

[655321]

I would lead ♠J.

Often it is best to lead our best suit against a slam (clubs here).
But this time I am hoping that we can still get our club trick - declarer's hand is the one with shorter clubs, and he won't usually be able to pitch his clubs on dummy's suits.

[jdonn]

Club seems blatantly obvious to me. It's not just right in theory to lead aggressively vs slams like this, it has worked out well for me time after time.

[Old York]

A trump lead is just as likely to succeed here. Declarer needs to establish his hearts by ruffing, or maybe establish dummy's club suit
Declarer should not have xx in either black suit to bid 4NT

Tony

[whereagles]

Opps threaten to setup the hearts for a discard, but that's only a problem if diamonds are like 5-4. With 4-4 declarer needs to ruff a heart and then you get no club discard.

Diamonds are more likely to be 4-4, so ♠J.