[Cyberyeti]

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What if anything does the second double show and what do you lead ? (IMPs)

[helene_t]

I don't think the double suggests anything other than that he hopes it goes down.

I lead a club.

[DavidKok]

I'm more interested in what the first double shows. Normally Lightner asks for an unusual lead, suggesting ruffing values. If partner has got a heart void they have no way to tell that we don't have a natural heart lead anyway (maybe we held KQJxxx). So double should promise a black suit void. The question them becomes: did the opponents hide their 9-card spade fit, or their 10-card club fit?
3♥ wasn't alerted, so surely North thinks it was standard. I think that practically excludes 4 or more spades, and I don't think East has got a 6-card suit (if anything, East wouldn't have the requisite stoppers for 6NT). So partner must be void in clubs, have weak hearts (because East felt comfortable running to NT) and therefore have decent spades and some diamonds - maybe something like 6=3=4=0, and no desire to enter the auction over 3♥? That makes no sense at all though - we could figure out this much from the first double, and the second double warns us away from the lead that the first suggested.

So maybe partner is void in hearts after all, and thought it necessary to tell us to lead our own suit? But how did they know that would be unusual for us? Do we have an agreement to not preempt on suits better than QT9xxx?

I think I have to stick with my initial read - declarer has got a huge hand with both minors, maybe something like ♠x, ♥A, ♦AKQxxx, ♣AJxxx, and when partner North denied spades and denied a heart stopper South saw 12 tricks in diamonds. But the Lightner double killed the club tricks, and so they gambled on North having the ace of spades for the GF 3♥ bid.

Scratch all that - if partner has got spades, a few hearts and couldn't act over 3♥ we don't have a score to protect. With that hand partner would pass 6NT, trusting us to lead a spade based on the above. So why double again? Did partner understand that we'd figure this all out, and felt confident they could double for a better score without creating ambiguity? Also, who am I kidding, it is far more common that partner saw a heart void, ignored the auction, and doubled to remind us that we have a long suit ('Thanks, I noticed'). In that case the lead is a tossup. Do you have any other lead-directing doubles agreements, for example asking for a spade lead against 3NT?

[johnu]

Cyberyeti, on 2022-March-25, 14:08, said:

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What if anything does the second double show and what do you lead ? (IMPs)

What does the 1st double ask/show? Standard Lightner double? And if so, what would you lead against 6♦ if South didn't pull to 6NT?

So, it sounds like East has AK in one of the black suits. Between clubs and spades, AFAIK, it's a total guess. South could have 4 spades to AKQ10 so a spade lead would give up a trick, and South wouldn't bother trying to find a spade fit since North didn't make a negative double. If South needs a club finesse, the odds favor finessing East after the 2♥ jump overcall.

[mikeh]

The first double merely said ‘I can beat 6D’. It didn’t promise a void anywhere. Give him, say, Axxxx xx J1098 xx and he doubles because it’s virtually impossible, from his POV, that either opp has a spade void….few would bid 2H with a side 4 card spade suit and, even if that had happened, the odds of the suit being 4-0 are very low. Hence the double.

The same hand might well double 6N. Where the heck are they getting 12 tricks with only 3 diamond tops? Again, from his POV he can hardly pass out of fear that the hand is a true freak with responder having 7 clubs or 6 clubs and, on a heart lead, 3 hearts.

If you don’t agree with J1098 in diamonds, make it QJ10.

However, the pull to 6N tells us that east almost surely expects no diamond losers but is very worried about a ruff.

The double ‘should’ imo say that either it doesn’t matter or we need a heart ruff. Sure, if we held KQJxxx we’d lead it anyway, but would we really lead a heart from KJxxxx after he failed to double 3H? He denies a heart honour by that pass….hence the only way to assure a heart ruff is to double.

Also, he doesn’t expect to beat 6D with a longish black suit headed by the AK….he has no reason to think we’d lead that suit after his double…indeed, we should NOT lead a black suit then plus, of course, there is nothing about the auction that says AK from length are cashing.

So since by far the most likely suit in which he is void is hearts….opener expected AKxx to be a great holding since he’d pull trump and ruff two hearts in dummy….now he suspects that hearts are getting ruffed by partner. So he’s hoping responder has a parking space for his hearts, in a black suit…inferentially clubs. Which implies that he himself has short clubs, otherwise he’s not getting many pitches.

Ok…that analysis seems to handle the first double and the pull to 6N. What does the second double mean?

I go back to the possibility of an ace and a natural diamond winner, with or without a heart void. In that case it likely doesn’t matter what we lead. So we ignore that.

We’re not leading hearts, because that can’t ever be correct after the pass over 3H.

I reject the notion that opener has a minor two suiter. While I often agree with David, I don’t understand why declarer would think that we’d find a club lead against 6D doubled. I think the double, if on a void, would be almost universally understood as a heart void.

At the table I’d know how many diamonds 1D promised. If it would be systemic on say 4432 then dummy has 5+ diamonds. If it promises 4, then dummy might hold only 4…..increasing the odds of say 1=3=4=5

Placing cards is a fool’s game most of the time…we’re almost never getting it more than vaguely right. However, on auctions like this, we have to place a bet despite the low confidence we can have.

So something like x xxx Kxxx AKQJx opposite QJx AKJx AQJxx x

I’m assuming 3H was a gf diamond raise and that 3S would not have been a splinter. Again, at the table, I’d know whether those assumptions were correct. If 3S were a splinter, then that construction falls away

But I’m going with his holding a black AK and a heart void. If he has the club AK, we may not need to lead it since responder is marked with some club length, and opener probably lacks the major winners needs to score 12 tricks in 6N without a club trick.

Hence I’ve talked myself into partner having something akin to AKxxx void xxxx xxxx

Do I think this (not this exact but approximately this) is ‘probable’? Not at all. I have low confidence in any construction but ‘less low’ on this than on any other where it matters. Given that this was posted, I suspect it does matter. At the table, I’d assume it mattered but think it’s odds-on that it doesn’t.

[Cyberyeti]

Interesting analysis Mike:

3♠ would have been fit not splinter.

1♦ showed 4

[mikeh]

Cyberyeti, on 2022-March-26, 01:22, said:

Interesting analysis Mike:

3♠ would have been fit not splinter.

1♦ showed 4

‘Interesting’ is never good to read😀 it means I’m wrong! Neither the first nor the last time but one does what one can

[Cyberyeti]

mikeh, on 2022-March-26, 01:26, said:

‘Interesting’ is never good to read😀 it means I’m wrong! Neither the first nor the last time but one does what one can

I'm going to wait a little before I reveal the actual hand, you may be right (whether for the right reasons or not), you may not, but it was a much deeper analysis than anybody else's.

[DavidKok]

mikeh, on 2022-March-26, 00:24, said:

[...]

Hence I’ve talked myself into partner having something akin to AKxxx void xxxx xxxx

Do I think this (not this exact but approximately this) is ‘probable’? Not at all. I have low confidence in any construction but ‘less low’ on this than on any other where it matters. Given that this was posted, I suspect it does matter. At the table, I’d assume it mattered but think it’s odds-on that it doesn’t.

I think this hand would never double 6♦. Partner will lead a heart most of the time, and a spade the rest of the time. They can't lead a diamond on the auction (surely the opponents have a 9-card fit for all that jumping around), and as you say partner will never find a club lead on their own. So pass and take the -1 or -2 we have coming our way. That's why I ruled out a heart void - but then I can't find a hand consistent with a second double.

My best guess is that at least one of the doubles was a mistake, and we have to figure out which one.

[mikeh]

DavidKok, on 2022-March-26, 02:56, said:

I think this hand would never double 6♦. Partner will lead a heart most of the time, and a spade the rest of the time. They can't lead a diamond on the auction (surely the opponents have a 9-card fit for all that jumping around), and as you say partner will never find a club lead on their own. So pass and take the -1 or -2 we have coming our way. That's why I ruled out a heart void - but then I can't find a hand consistent with a second double.

My best guess is that at least one of the doubles was a mistake, and we have to figure out which one.

Why on earth would anyone lead a heart against 6D unless they hold the ace or a sequence? I defy you to construct a hand on which the heart lead makes any sense at all if one holds, say, KJ10xxx

The one thing we know with utter certainty is that partner does not hold either the ace or the queen….he has an automatic double of 3H with that hand. Remember, over 3H he doesn’t know they’re heading for slam. Why should he assume we have a bad 3 count? We know he has an ace and something more, and we could easily hold an additional 4 or 5 hcp. Why shouldn’t he steer a safe/killinglead against notrump? Or a safe lead v 5D?

Admittedly leading low from the ace against 3N isn’t wonderful if he has the queen, but if we listen to the auction, and opener bids 3N over the double (and we hold, say, AJxxxx) we know where the king is and can decide whether to try to find his entry or lead a heart, risking giving him his 9th trick.

Rather than play partner for a mistake, I’m going to try my best to construct a hand where both doubles are right.

Imagine: partner makes two intelligent doubles but you assume he’s screwed up so you make a lead that gives away the contract. You’ll feel embarrassed and your partner will wonder why he’s playing with you.

Now, maybe I’m spoiled since my two regular partners generally think before they double both 6D and 6N. Neither they nor I are perfect but all of us approach bridge from the point of view that partner probably hasn’t made a silly bid or play. I wouldn’t want to play in any other kind of partnership.

[Cyberyeti]

FWIW I agree with Mike that the first X almost certainly shows a heart void. The point of the post was whether there was a difference between pass and double second time round with one at least say suggesting a spade and the other a club (by omission of a double for a spade) or vice versa.

[LBengtsson]

I had to smile, Cyberyeti This is posted in the intermediate and advanced forum, and whilst it may have been played at that level it is a 'ask a expert' question.

I have looked at David and Mikeh's analysis and wonder why after East passes 3♥ South jumps to 6♦ second bid! That is amateur bidding, gambling bidding, or expert searching for an IMP swing (or MP trying for a top) bidding so I would want to know also who I was playing against and what conventions they had available to them.

At IMPs I would want to know what 3♥ meant exactly - ♦ support, asking for a ♥ stop or ♦ support with ♥ stop (and that is not likely) or, just ♦ support. It seems a strange bid given that there are X, 2♠, 2NT, 3♣, 3♦ bids available so I would want to know what all these meant to the partnership also.

That said, the X of 6♦ does not have to be Lightner, and the X of 6NT does not have to be special. East might be putting the contract down by himself as mentioned in previous posts.

And what if your partner X the opps. 3♥ bid, does that show ♥ support with an honor, is that available also? The one (very obvious) conclusion I can know is that South must have a big hand for this auction, but whether it is a hand with a second suit of ♣, ♥ or ♠ is a guess imo.

If East always uses a X at the 6 level as Lightner, and Lightner X usually says to partner to lead your long suit as I will be void, or a second suit where the opponents have bid but not played the contract, then on this auction, with the absense of knowing the opps. second suit, I would expect partner to the void in ♥. But does not seem likely.

Whether I could work out all of this, or every other combination of thoughts at the table and not be penalized for time is another matter lol!

In answer to the original question "Does this X suggest anything specific" the only conclusion is that East has a ace and a natural ♦ trick. Maybe East has ♥A stiff and used Lightner X so that it made you you lead a ♥ against 6♦ that is also possible imo.

I am no nearer a solution, and it is one for post mortem. I have feeling in my gut that if you lead the wrong suit the slam will be made, declarers and dummys losers being discarded on a second suit. That said I think the safest lead is a ♣ but I am probably wrong.

[Cyberyeti]

The jump to 6♦ suggests to me that opener has plenty of diamonds and probably one of the blacks open, maybe xxx and thinks he might have a chance if the right suit isn't led (or Axx and a trump loser), but just possibly 3 losers in said black suit or two and a trump so 5♦ isn't safe.

[DavidKok]

mikeh, on 2022-March-26, 04:39, said:

Why on earth would anyone lead a heart against 6D unless they hold the ace or a sequence? I defy you to construct a hand on which the heart lead makes any sense at all if one holds, say, KJ10xxx

The two points are

• If East doesn't double 6♦, West likely has no reason to pick any particular non-heart lead.
  
• If East has a heart void, they have no way to tell that West does not have a natural heart sequence to lead from.

Based on this, I think that a double of 6♦ should ask West to lead a non-heart, and a pass should ask West to make their natural lead (which is likely to be a heart). East can send only one bit of information, and a double may be costly if 6♦X makes. So it had better be narrowly defined.

mikeh, on 2022-March-26, 04:39, said:

Rather than play partner for a mistake, I’m going to try my best to construct a hand where both doubles are right.

Imagine: partner makes two intelligent doubles but you assume he’s screwed up so you make a lead that gives away the contract. You’ll feel embarrassed and your partner will wonder why he’s playing with you.

Now, maybe I’m spoiled since my two regular partners generally think before they double both 6D and 6N. Neither they nor I are perfect but all of us approach bridge from the point of view that partner probably hasn’t made a silly bid or play. I wouldn’t want to play in any other kind of partnership.

This entire text is just petty. Did you miss my previous post, where I tried to construct hands for partner that make sense on the auction consistent with my interpretation of the double on 6♦? I don't habitually assume partner made a mistake, but I genuinely figured the double of 6♦ shows a club void, after which we have a natural spade lead against 6NT, and the double should then suggest a heart lead. And that's where I got stuck, since I had too much difficulty finding a hand consistent with the auction on which a heart lead was necessary. The obvious, logical, conclusion is that the double of 6♦ showed a heart void - but I could only deduce this after the double on 6NT! So as I understood it, the double of 6♦ was a mistake in that it asked me for a club lead - which would have let the contract make on layouts where the double of 6NT was correct.
I'm not daft - of course after seeing the entire auction partner likely has a heart void and wants a black suit lead against 6NT. But in my partnership we double slams for an unusual lead, which rules out the long suit we bid. We also don't habitually double 3♥ to show an honour - the extra space for the opponents on their GF auction is on balance a loser compared to catering to partner having a garbage weak jump shift. Partner bid 2♥, and they are expected to lead hearts unless something exceptional happens.

Cyberyeti, on 2022-March-26, 05:00, said:

FWIW I agree with Mike that the first X almost certainly shows a heart void. The point of the post was whether there was a difference between pass and double second time round with one at least say suggesting a spade and the other a club (by omission of a double for a spade) or vice versa.

Given the double on 6NT I agree that partner probably has a heart void, but I think agreeing that doubling 6♦ asks for a heart lead is a mistake.

LBengtsson, on 2022-March-26, 07:08, said:

That said, the X of 6♦ does not have to be Lightner, and the X of 6NT does not have to be special. East might be putting the contract down by himself as mentioned in previous posts.

[..]

If East always uses a X at the 6 level as Lightner, and Lightner X usually says to partner to lead your long suit as I will be void, or a second suit where the opponents have bid but not played the contract, then on this auction, with the absense of knowing the opps. second suit, I would expect partner to the void in ♥. But does not seem likely.

I also disagree with these two statements. This is IMP scoring, we do not chase +200 or +100 when the opponents get into a weird slam. A lead-directing double that sets the contract instead of letting it make is a 14-IMP swing (opps NV) or 16-IMP swing (opps V), while doubling for penalties if they were going down anyway is a 1-IMP swing against game at the other table (regardless of vulnerability). Of course you can double if it doesn't matter anyway, but based on the IMP odds all doubles at this level should be assumed to be Lightner until proven otherwise - you're just taking on approximately 15 to 1 odds against if you don't. Also the meaning of a Lightner double is not to lead your long suit, but to lead the suit that you would otherwise not have led. After all, if the suit you would have lead anyway sets the contract, partner would not have needed to double. Or, more formally, if the total variation between partner's expectation of which leads will set the contract and partner's expectation of which lead we are likely to choose differs by more than ~7% (1/15), it is good odds to give a lead-directing double if that asks for an unusual lead. If the meaning of a double is different the gap needs to be larger, and can be used to good effect less often. At IMP odds these large the value of information is huge, and doubling on a heart void fails to take into account that we now lose on all the deals where we need a non-heart lead (which is going to happen more often).

Or, put differently, if we make a little 2x2 cross-table of "partner leads a heart", "partner leads a non-heart", "we double", "we do not double", which meaning of double would maximise the IMPs in the long run?

[smerriman]

My opinion counts for very little here given the level of people replying already, but..

My definition of a Lightner double is that it specifically excludes any suit bid by the defenders, as is shared by many online sources:

Karen Walker: "That eliminates a lead of the unbid suit, a trump or any suits bid by you or partner. "
Bridgebum: "Additionally, the double asks partner to NOT lead any suit that your side has bid. "

Now obviously I'm not saying any of the posts above were wrong; I'm sure in expert circles you can get more complex and play "don't lead your suit, unless you know that I'll know that you weren't going to lead it, in which case lead it". But there's no chance I'm ever making that agreement at the Intermediate/Advanced level, which is where this was posted; all that's going to do is lead to disaster. So I'll trust our partnership agreement.

They can't have a spade void on the bidding; they might have something like an ace and a sure diamond trick, but wouldn't double with that due to the risk of running to 6NT. So as unlikely as it seems, a club void seems the only option, perhaps with the AK of spades. I lead a spade.

[mikeh]

DavidKok, on 2022-March-26, 16:37, said:

The two points are

• If East doesn't double 6♦, West likely has no reason to pick any particular non-heart lead.
  
• If East has a heart void, they have no way to tell that West does not have a natural heart sequence to lead from.

Based on this, I think that a double of 6♦ should ask West to lead a non-heart, and a pass should ask West to make their natural lead (which is likely to be a heart). East can send only one bit of information, and a double may be costly if 6♦X makes. So it had better be narrowly defined.

This entire text is just petty. Did you miss my previous post, where I tried to construct hands for partner that make sense on the auction consistent with my interpretation of the double on 6♦? I don't habitually assume partner made a mistake, but I genuinely figured the double of 6♦ shows a club void, after which we have a natural spade lead against 6NT, and the double should then suggest a heart lead. And that's where I got stuck, since I had too much difficulty finding a hand consistent with the auction on which a heart lead was necessary. The obvious, logical, conclusion is that the double of 6♦ showed a heart void - but I could only deduce this after the double on 6NT! So as I understood it, the double of 6♦ was a mistake in that it asked me for a club lead - which would have let the contract make on layouts where the double of 6NT was correct.
I'm not daft - of course after seeing the entire auction partner likely has a heart void and wants a black suit lead against 6NT. But in my partnership we double slams for an unusual lead, which rules out the long suit we bid. We also don't habitually double 3♥ to show an honour - the extra space for the opponents on their GF auction is on balance a loser compared to catering to partner having a garbage weak jump shift. Partner bid 2♥, and they are expected to lead hearts unless something exceptional happens.

Given the double on 6NT I agree that partner probably has a heart void, but I think agreeing that doubling 6♦ asks for a heart lead is a mistake.

I also disagree with these two statements. This is IMP scoring, we do not chase +200 or +100 when the opponents get into a weird slam. A lead-directing double that sets the contract instead of letting it make is a 14-IMP swing (opps NV) or 16-IMP swing (opps V), while doubling for penalties if they were going down anyway is a 1-IMP swing against game at the other table (regardless of vulnerability). Of course you can double if it doesn't matter anyway, but based on the IMP odds all doubles at this level should be assumed to be Lightner until proven otherwise - you're just taking on approximately 15 to 1 odds against if you don't. Also the meaning of a Lightner double is not to lead your long suit, but to lead the suit that you would otherwise not have led. After all, if the suit you would have lead anyway sets the contract, partner would not have needed to double. Or, more formally, if the total variation between partner's expectation of which leads will set the contract and partner's expectation of which lead we are likely to choose differs by more than ~7% (1/15), it is good odds to give a lead-directing double if that asks for an unusual lead. If the meaning of a double is different the gap needs to be larger, and can be used to good effect less often. At IMP odds these large the value of information is huge, and doubling on a heart void fails to take into account that we now lose on all the deals where we need a non-heart lead (which is going to happen more often).

Or, put differently, if we make a little 2x2 cross-table of "partner leads a heart", "partner leads a non-heart", "we double", "we do not double", which meaning of double would maximise the IMPs in the long run?

David: your analysis doesn’t appear to take into account what is to me the key factor on the hand: the pass over 3H

Now, if your partnership style is that 2H always shows an honour sequence, then my argument falls away. But I am completely sure that it doesn’t…even if for some weird reason you personally would prefer that 2H always show a suit that can safely be led, the actual hand shows that this partnership doesn’t play it that way.

I think, with respect which is genuine, that you’re also failing to consider the auction from your partner’s point of view. There is no way that he can nor should assume that you have a natural heart lead!

This is the point. He knows that he didn’t double 3H. He therefore knows that you know that he has none of the A/K/Q of hearts.

Thus he knows that you know that a heart lead from a broken suit is ALWAYS surrendering a trick….in a slam! Always, that is, unless you have a void in the suit or an opp has a stiff Ace.

Your analysis of why and when we double a slam is, imo, quite reasonable although I think you underestimate the frequency with which one doubles that which is in front of one. One doubles whenever one has the contract beaten even if partner makes a horrible lead. Say I held nothing but the diamond AK and say QJ10 in spades. Ok, not likely but it’s an easy example with which to make one’s point. On the auction they can’t possibly run successfully to 6N…there isn’t any hand consistent with the auction on which they can score 12 tricks without a single diamond trick.

But we can and should, for lead purposes, ignore such hands. We should always assume double asks for a lead that would be unusual given the auction.

Here, absent a double of 6D, we would on many occasions be guessing as to which black suit…because on many hands we KNOW that a heart lead will cost a trick. What’s critical is that partner knows this….and knows that we know he knows this.

Since there are, as both he and we know, many, many 2H bids on which we’d never lead a heart, absent the double, the double tells us…‘don’t worry….lead a heart’.

To repeat: after he doesn’t double 3H he has a reasonable expectation that we will be trying to guess which black suit to lead unless he sends us a message telling us it’s necessary to make the lead we’d normally never consider.

What, you may say, about hands where we hold say KQJxxx in hearts? We’d usually lead that suit so doesn’t the double say lead something else?

No…because both he and we know that the double is catering to those common hands on which, were he not void, a heart lead would be disastrous.

When we analyze what the double means we have to keep the auction in mind. Has he doubled 3H, then a double of 6D tells us to lead a black suit, since in that auction a heart lead will normally not hand the opps a twelfth trick…at least nowhere as often as would a ‘wrong’ choice of black suit. Thus a double, after doubling 3H, would say: lead something else.

Having passed 3H, he no longer expects a heart lead. Thus double says lead hearts.

Sorry to be so repetitive. It’s almost 4 am and I’m trying to go back to sleep rather than edit😀

[DavidKok]

I think we disagree on which hands would double 3♥ then. We do not habitually double that on Hx, and so the inference that partner should not lead a heart if we do not take action is much weaker. Our ideas are that, firstly, the double gives the opponents two extra steps with which to coordinate where to play (pass = no stopper, redouble = a full stopper but I want you to play 3NT or it was an advance cue, 3NT = half a stopper (positional) - as an example of how doubling can be very expensive on routine hands) and secondly it is unlikely that partner not being sure of our honour holding will look for a different lead more than 50% of the time. Sure, sometimes partner leads from a broken sequence when it is wrong, or fails to lead from one when it is right, but more often this does not happen.

[LBengtsson]

This is a interesting forum post. It is making me think. I have credited +1 to both DavidKok and mikeh without knowing who is right. (And Cyberyeti for the post.) My contribution is not on their level. However...

My understanding of a Lightner X is partner is to inform partner to find a unusual lead. I have just looked at the wiki page for this and it said the same (I am glad that my knowledge of bridge is right here lol!)

Lightner X are, as far as my knowledge knows, made primary for suit contracts where partner can gain a trick by a ruff. Now variations and partnership understanding and agreements could change that priority. Especially if one partner has bid a suit. As I said East could be putting any slam down without any help from West, and if that is so I have no worries gaining a few extra IMPs by X. It would be a fool to be East and X knowing that you can not beat the slam, surely?

I think the most important part of this auction is East's failure to X 3♥ suggesting a doubleton honor. So a ♥ lead against 6NT looks a danger. That is why I lead a ♣ as helene_t said.

Edit: I was writing this at the same time as David's above post but he posted first

[Cyberyeti]

This is the hand, in fact all actions whether technically right or not could work well. Find the right lead 6Nx-4, find the wrong lead it makes, the lightner is needed to beat 6♦.

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What was in the back of my mind was the double of 1N-3N which some people play as "lead a spade", and whether a double of a slam where you have essentially a blind choice of suits should have any agreement to it as to which is suggested by a double.

[mikeh]

DavidKok, on 2022-March-27, 02:40, said:

I think we disagree on which hands would double 3♥ then. We do not habitually double that on Hx, and so the inference that partner should not lead a heart if we do not take action is much weaker. Our ideas are that, firstly, the double gives the opponents two extra steps with which to coordinate where to play (pass = no stopper, redouble = a full stopper but I want you to play 3NT or it was an advance cue, 3NT = half a stopper (positional) - as an example of how doubling can be very expensive on routine hands) and secondly it is unlikely that partner not being sure of our honour holding will look for a different lead more than 50% of the time. Sure, sometimes partner leads from a broken sequence when it is wrong, or fails to lead from one when it is right, but more often this does not happen.

Surely the single most common bid by opener over 3H is 3N, at any form of scoring. It’s basically automatic with any balanced or semi balanced hand other than a very strong one. Then the 2H bidder has to guess on opening lead.

By doubling wit an honour, advancer does two things. One: he gets the lead most likely to set the contract and two: he may persuade the opps not to play 3N when they have one stopper but responder has extra diamond length such that 9 tricks are available

To me, these far outweigh the cost of giving opener a pass or a redouble. Now, some. Very good pairs will have an agreement such as xx shows a partial stop,enabling responder to bid 3N when the combined holding is Jxx opposite Qx. Of course those pairs may sometimes play Qx opposite Jx😀

Anyway, we’ve isolated the source of disagreement