[pescetom]

Even that other forum was inconclusive about this simple but important and not infrequent choice: should one lead the King of partner's suit against their suit slam, or merely encourage?

Curious to know what others on this forum think, particularly more expert players.

[jillybean]

Good question.
My tendency would be the 4, but Im less expert than most.

[Huibertus]

In general you need to assess which opponent is most likely to hold a singleton ♣, the risk is partner or you cashes a high ♣ and the other one gets ruffed out by a ruffing finesse. Also in general you should assess whether or not it is important to hold the first trick, see what is in dummy and decide how to continue. The final consideration is "Can your partner be sure how many ♣ can be cashed knowing how long you are, or do you need to get count by leading the King and you are the one best to use the information.

On this specific hand I would assess West to be the hand most likely holding a singleton ♣ but I don't think it matters as partner wouldn't double on just holding the Ace (or just the Queen) so there is no ruffing finesse if this is the case (maybe I'm wrong, in my circles nobody plays control answers). I don't think holding the first trick is important on this hand either. So if we lead 3/5 I'm leading low as partner should be able to see I hold a 3 card. If we lead 2nd/4th I'm leading the King to get count, as partner when I'm leading the 9 potentially wouldn't be able to see if it's a 2 or 3 card or if you lead the 4 from this holding potentially wouldn't be able to see if this is a 3 or a 4 card.

[DavidKok]

My answer is split in two:

Firstly, I would lead whatever is systemic. This may sound like a copout, but I've had far more accidents with me or partner getting 'brilliant' and leading 'the card that is, obviously, most useful' and it subsequently being impossible to read, than I've had accidents from the systemic lead costing. Even in the situations where it is important for one side to stay on lead, we sometimes fail to find the winning contiuation after, and it was more a post-mortem option than a realistic possibility at the table.

Then for the natural followup question: what should your lead agreements be in this situation? Maybe they should be special at the slam level, or facing a lead-directing double, or both conditions need to be met for the exception to apply. My personal approach to this is: keep your normal lead agreements, and only consider making exceptions after it's caused a loss at the table (and even then, don't change your agreements on the fly! Only during a system discussion some days after the match). My normal lead here is the 9 (2nd/4th, Polish style) in some partnerships and the 4 (odd leads) in others. I think the king is likely more effective, but partner may well confuse this for Kx or K tight. More generally, I think it is quite common to combine massively overcomplicated lead and signaling agreements with mediocre to poor integration of this information into a game plan. I much prefer simple signals, possibly with somewhat sophisticated rules on which applies when, to detailed and complicated lead and signaling agreements. Or, put differently, in my experience most losses on defence are caused by rudimentary errors that no signalling scheme can hope to solve.

[WasWinM]

I say lead the king—about as often as you find a genuine pearl in the oysters you’ve been served. Just don’t go off half-shelled and do it more often, only when absolutely necessary.
PS: I have yet to find a pearl.

[pescetom]

Thanks to those who replied so far. I hope others will contribute too and so I'll save any comments and questions until later on.

One thing I was surprised nobody commented on so far - on either forum - was the rather odd auction of EW and how it might influence our choice.
They are a very experienced pair, with the advantages and hindrances that come with old age and marriage
I deliberately omitted to complicate the problem with any UI, but inevitably there was some, although minimal: 3♠ was firm and rather fast, 4♠ a little slow.
West did not look happy about the final contract.
My thought during the auction was that West could not have been hoping for more than 2 keycards from 4 half-controls and so must be concerned about a missing ♠Q, but that did not fit easily with East's raise to 6♠: maybe she had now decided her long trump support was worth the Q, or maybe she had a clubs void?
But FWIW I decided that whatever is going on, the most likely scenario is West with a clubs singleton.

[DavidKok]

It's definitely odd for the weak and limited hand to push to slam after a 5♠ signoff. I assumed the "4♠ as RKCB spades" was a typo and it should be 4NT. Then again people make such messes of their slam actions, it takes more than this to surprise me. A lot of people get very excited when they think they might be able to bid a slam.

I dislike the EW methods, but that has no impact on my decisions now. If there were breaks in tempo we should call a director independently of our lead agreements.

[pescetom]

 DavidKok, on 2025-July-27, 09:50, said:

It's definitely odd for the weak and limited hand to push to slam after a 5♠ signoff. I assumed the "4♠ as RKCB spades" was a typo and it should be 4NT. Then again people make such messes of their slam actions, it takes more than this to surprise me. A lot of people get very excited when they think they might be able to bid a slam.

I dislike the EW methods, but that has no impact on my decisions now. If there were breaks in tempo we should call a director independently of our lead agreements.

Yes 4♠ on the other forum was a typo for 4NT: I never figured out how to correct an error after viewing the complete page but before confirming Publish.

The variations in tempo were quite unremarkable in the context of a club tournament without screens, I mentioned them only to replicate my feel at the table (West was keen on his spades and East had more than a minimum).

[bluenikki]

pescetom, on 2025-July-26, 14:34, said:

Even that other forum was inconclusive about this simple but important and not infrequent choice: should one lead the King of partner's suit against their suit slam, or merely encourage?

Curious to know what others on this forum think, particularly more expert players.

It's your only time on lead. I'd certainly lead the king, hoping it holds and I might guess what to do next.

Of course, I have a history that favors leading kings against slams. In the 70s, before Grand National Teams were flighted, we were at the divisional stage, heavy underdogs. We were clearly doing badly. But then, our opponents bid a naughty suit slam. I led from a side-suit king. My late wife won the ace and .... shifted. A friend suggested I might lead the king. If it's the right suit to lead that shouldn't matter.

[pescetom]

Thanks to those who replied. Still hoping to hear from mike_h, but it already seems clear that we are split here, just like that other forum. It's interesting at least to know more about why.

bluenikki, on 2025-July-27, 15:01, said:

It's your only time on lead. I'd certainly lead the king

That's certainly how I see it and saw it, hence the poll. But my first-time partner in North is a better player than I am, and chose not to lead the King, as have other partners in similar situations in the past. To confuse me further, she agreed during the post-mortem that it would have been right to lead the King, but that may have been diplomacy.

I guess a lot of what is making the difference here is about whether one has a habit of thinking out of the box when confronted with an unusual situation or whether one tends to follow generic agreements all the same (to the point of giving count here).
As Davidkok says, it is certainly better to follow our generic agreements where partner will expect that: I am not one to play guessing games and would not want to throw the King in the face of a partner who blindly expects count.
I guess what I learned here is that I will be lucky to find a like-minded out of the box partner and until then should never assume partner denied the King.

[TMorris]

king for me. I don't want anything led through to me, perhaps partner might and when the King holds I will know better what to do.