[thepossum]

Dear all

I'm no expert but when you have 0 or 1 keycards showing a void is not very useful

In fact showing a void is of more use to the defence

Does anyone do it other than GiB

I could post an example of a marginal slam that needed a lead through the void

Sitting there a bit short with AKQxx of something. Maybe even AKQJx or AKQTx

Yours
Perpetually Perplexed

[DavidKok]

Sometimes slams fail. I don't see why showing voids is especially bad when holding 0 or 1 key cards, compared to when holding 2 or more.
In general:

• Some good partnerships use methods to show voids before getting to the level of asking keycards (outside competition, at least). This partially eliminates the problem.
  
• As always, if you add a widget to your agreements (in this case, void-showing responses to Blackwood), you need to be prepared for the consequences. Keep in mind that you should only bid 4NT if you are prepared for partner's answer. This widget adds sharper constraints to that, especially since you will be forced to the 6-level (or 5NT) if partner does show a useful void.
  
• In general optimising your Blackwood responses is, in my opinion, time better spent somewhere else. I play a complicated version of RKC Blackwood and it has served me well (based on a 17-part! series available on d17acbl.org, but it seems to have been taken down. It is still available on the web archive, and I also had the foresight to save a copy), but it is not at all a core part of the bidding system.

[P_Marlowe]

Hi,

I have no idea, what scheme GIB is using, but with 0 key cards, you usually dont show the void.
https://www.bridgebu...m/blackwood.php

With 1 or 2 KC, if the partner pulls out RKCB and you have 1 or 2 KC and a useful coid, this should be enough,
otherwise RKCB was wrong.
In case you have the add. void, ... this is geared toward Grand slam.

With kind regards
Marlowe

[Stephen Tu]

Showing 0 key cards and a void and forcing to slam as GIB does is ridiculous. Showing 1 key card and a void, IMO, is not much better. How do you know if your void is "useful" or not? The main thing I find is that you've splintered at some point, or maybe cue bid the suit, but partner holds like Axxx in the suit and thinks there isn't duplication and is facing a singleton, but with ace opposite void there is, and there is something crucial missing elsewhere. Having void rather than singleton in this case doesn't decrease the number of losers in the suit and often doesn't decrease number of losers overall.

Basically I think it works a ton better to try to arrange system to show voids below your keycard asking level, and not deal with void showing responses, at least the 0/1 variety. 2+ I can probably live with.

[DavidKok]

 Stephen Tu, on 2021-November-19, 06:19, said:

How do you know if your void is "useful" or not?

The first few rounds of bidding, before Blackwood, typically provide a clue.

[AL78]

 Stephen Tu, on 2021-November-19, 06:19, said:

How do you know if your void is "useful" or not?

If it is in a suit bid by the opponents natuarally, or not in a suit bid by partner naturally?

[Stephen Tu]

 DavidKok, on 2021-November-19, 06:58, said:

The first few rounds of bidding, before Blackwood, typically provide a clue.

I don't think you can provide good example auctions of this. Often it takes a few rounds of bidding and maybe a jump or even a double jump just to show your shortness in the suit, and you've only shown shortness (singleton/void) there, not void specifically. Then there is no room for partner to say cue bid the ace of that suit or not (you are very often bidding 4 level to show the shortness), and partner eventually launches into rkc, and like I said you can't tell if partner has xxx opposite and the void is one trick better than a stiff, or Axx (IMO more common) and the void doesn't directly help you, and bidding 6 level to show 1 kc and stiff might land you at 6 missing 2 cashing keys, or like cashing key and a losing hook for trump Q since you've also blown up Q asking.

It works way better if you can specifically distinguish singleton vs void below 4 of trumps, or if the void holder is the one who can employ exclusion, IMO. But it can take significant gadgetry/relay system stuff to get it to work in general auctions. It's reasonably easy to get low void showing into stuff like say 1M-2nt raise auctions or direct 1M-splinter auctions though.

[Stephen Tu]

 AL78, on 2021-November-19, 07:21, said:

If it is in a suit bid by the opponents natuarally, or not in a suit bid by partner naturally?

If partner opens 1c on xxx or Jxx clubs, void is pretty useful in a suit contract. And if in the opponent's suit, the shortness is often useful, but a void is *not* one trick better than singleton if you show shortness there and partner is excited holding Axx opposite rather than xxxx.
So jumping to 6 suit to show 1 key + void is still very dangerous IMO, partner may already be assuming zero losers that suit holding the Ace and hearing your shortness, and was checking if 2 key cards missing outside or KC + trump Q, and 1 key might not be enough for that.

[pescetom]

 DavidKok, on 2021-November-19, 03:19, said:

Some good partnerships use methods to show voids before getting to the level of asking keycards (outside competition, at least).

If one of us has splintered or shown an unbalanced hand this is one more reason to investigate with Italian-style control-bids rather than RKCB, as this has the side benefit of distinguishing singleton/void without forcing to slam. So as you imply, I find void-showing RKCB replies are useful mainly in competition. They don't happen often, but FWIW I don't remember a time when the effective slam force turned out wrong, 1 keycard or not. I agree with you that there are much higher frequency issues to worry about.

[johnu]

 thepossum, on 2021-November-19, 01:30, said:

I'm no expert but when you have 0 or 1 keycards showing a void is not very useful

Even less so when the void is in trumps. GIB would never do that.... right?!?

[DavidKok]

 Stephen Tu, on 2021-November-19, 11:50, said:

I don't think you can provide good example auctions of this.

Something like 2♣* (strong, artificial)-2♦* (waiting); 2♠ (natural)-3♠ (stronger than 4♠); 4♣ (control)-4X (doesn't really matter for the example, even 4♠ signoff would work); 4NT* (RKC) would qualify.
Or, if you like opening 1♠ on strong shapely hands, 1♠-4♠ (preemptive); 4NT (RKC).
Or perhaps even 1♠-2♥ (GF NAT); 2♠ (Waiting)-3♠; 4♣ (control)-4♦ (control, responder happens to be 3=6=0=4); 4NT (RKC). I think this is the last chance responder will get to show the void.

The agreement is certainly low frequency - asking for keycards is low frequency to begin with, and for responder to have an undisclosed but potentially useful void is even rarer. As pescetom pointed out it is easier to construct an example in competition, although if there is too much competition I prefer to use 4NT for something other than keycards.

[Stephen Tu]

 DavidKok, on 2021-November-19, 17:20, said:

Something like 2♣* (strong, artificial)-2♦* (waiting); 2♠ (natural)-3♠ (stronger than 4♠); 4♣ (control)-4X (doesn't really matter for the example, even 4♠ signoff would work); 4NT* (RKC) would qualify.

Again, my criticism holds. How often does partner have Axx on this auction rather than xxx in the void suit? *Especially* when partner holds the 2c opener and is the RKC asker.

2c-2d;2s-3s;4c-4h;4nt-?, you've say cue bid your heart void. But at this point, partner doesn't know if your heart cue is stiff, void, or king, (or ace if he is looking at say KQx). If he is looking at AQx, how do you know that it is actually useful that you have a void H rather than a stiff? From his view it's zero heart losers either way, he might be using rkc to not bid it being off two keys outside of hearts. Answering your 6h to 4nt to show 1+ void may leave you too high.

2c-2d-2s-4h! spl is at least better, now at least partner knows it's a shortness control and not the K solidifying his AQJ(x) heart suit. Now if one had say 2c-2d-2s-3nt! defined as say undefined void, now you'd be getting somewhere useful.

Quote

Or, if you like opening 1♠ on strong shapely hands, 1♠-4♠ (preemptive); 4NT (RKC).

This is even worse IMO, the hands where the voids would most gain (no wastage in void suit) wouldn't be able to bid 4nt sanely to begin with.

Quote

Or perhaps even 1♠-2♥ (GF NAT); 2♠ (Waiting)-3♠; 4♣ (control)-4♦ (control, responder happens to be 3=6=0=4); 4NT (RKC). I think this is the last chance responder will get to show the void.

Again, when you cue bid 4d, partner doesn't know if it's A/K/stiff/void on this auction. Wouldn't you do the same on 3514? And shouldn't you spl over 2s instead to show it more directly? And again you don't know whether partner has xxx diamonds or Axx as to whether the void decreases your number of losers or not.
So to me answering > 5 trump suit just to show void is really dubious. And I don't really think that italian cues as pescetom really solves all problems either, as italian cues are mixed and Ks/aces are shown interchangeably. You get to find out *whether* a suit is controlled or not, but often you can't distinguish between hands where partner has Axx which works fine opposite your stiff (if you are the one asking), or KQx which would be much worse (you are off two aces). That's why most are doing mixed cues below 4M to find out if suits are controlled then an rkc ask to make sure not off two keys or key+ trump Q.

To me someone needs to show void below 4 trumps for it to work best, and if not possible probably partner of spl bidder should try hard to be the rkc *askee* (so spl bidder can use exclusion if appropriate), rather than the *asker*. But if partner beats me to asking keycards, if I have 1 with void, I am just making my normal 5 level response not 6. I've had disasters with partners who answered 6 with 1 and we were in 6 with no play.

[mikeh]

 Stephen Tu, on 2021-November-19, 18:23, said:

Again, my criticism holds. How often does partner have Axx on this auction rather than xxx in the void suit? *Especially* when partner holds the 2c opener and is the RKC asker.

2c-2d;2s-3s;4c-4h;4nt-?, you've say cue bid your heart void. But at this point, partner doesn't know if your heart cue is stiff, void, or king, (or ace if he is looking at say KQx). If he is looking at AQx, how do you know that it is actually useful that you have a void H rather than a stiff? From his view it's zero heart losers either way, he might be using rkc to not bid it being off two keys outside of hearts. Answering your 6h to 4nt to show 1+ void may leave you too high.

2c-2d-2s-4h! spl is at least better, now at least partner knows it's a shortness control and not the K solidifying his AQJ(x) heart suit. Now if one had say 2c-2d-2s-3nt! defined as say undefined void, now you'd be getting somewhere useful.


This is even worse IMO, the hands where the voids would most gain (no wastage in void suit) wouldn't be able to bid 4nt sanely to begin with.


Again, when you cue bid 4d, partner doesn't know if it's A/K/stiff/void on this auction. Wouldn't you do the same on 3514? And shouldn't you spl over 2s instead to show it more directly? And again you don't know whether partner has xxx diamonds or Axx as to whether the void decreases your number of losers or not.
So to me answering > 5 trump suit just to show void is really dubious. And I don't really think that italian cues as pescetom really solves all problems either, as italian cues are mixed and Ks/aces are shown interchangeably. You get to find out *whether* a suit is controlled or not, but often you can't distinguish between hands where partner has Axx which works fine opposite your stiff (if you are the one asking), or KQx which would be much worse (you are off two aces). That's why most are doing mixed cues below 4M to find out if suits are controlled then an rkc ask to make sure not off two keys or key+ trump Q.

To me someone needs to show void below 4 trumps for it to work best, and if not possible probably partner of spl bidder should try hard to be the rkc *askee* (so spl bidder can use exclusion if appropriate), rather than the *asker*. But if partner beats me to asking keycards, if I have 1 with void, I am just making my normal 5 level response not 6. I've had disasters with partners who answered 6 with 1 and we were in 6 with no play.

Stephen, I can’t imagine having an auction in which one partner keycarded, responder showed one keycard and a useful void and slam had no play. While you may be able to show me such a hand and persuade me that the keycard ask was appropriate, I have my doubts.

We DO NOT keycard unless we already have slam values on the auction so far, and we DO NOT routinely show the void…it has to be that rare bird: a useful void.

As for it being useful…let’s say partner keycarded with a side suit in which we’d splintered but been unable to show the void. Now it’s a useful void, provided we have sufficient trump or pitches available

[Stephen Tu]

 mikeh, on 2021-November-19, 23:12, said:

Stephen, I can't imagine having an auction in which one partner keycarded, responder showed one keycard and a useful void and slam had no play. While you may be able to show me such a hand and persuade me that the keycard ask was appropriate, I have my doubts.

We DO NOT keycard unless we already have slam values on the auction so far, and we DO NOT routinely show the void…it has to be that rare bird: a useful void.

As for it being useful…let's say partner keycarded with a side suit in which we'd splintered but been unable to show the void. Now it's a useful void, provided we have sufficient trump or pitches available

Something like:

---

N/S don't have tools to show void spl. 1s-4h!-?. South think slam is probably pretty good bet though not 100% opposite 2 keycards. But now North presumes void is useful and there you are in slam?
I just don't see how you can tell when the void is useful or not, when partner often has the ace in the suit, and void rather than stiff may not be helping you at all. Now if you can arrange an auction where partner specifically denied any control in that particular suit, then maybe you can tell, but when slam auctions come up it seems all too often I've only shown singleton or void (and sometimes not even that, can only show control in the suit which could be A/K/shortness), and have no idea whether partner is looking at the ace of that suit or not. So basically I can practically never tell useful or not so I routinely do *not* show the void by responding 6 to RKC.

[DavidKok]

I think being certain that the void is useful is sufficient but not necessary to consider the 5NT/6X bid. I was worried you would stick to your guns about your criticism, which is why I specifically mentioned in the third example that this was the last chance to show the void. Maybe partner is probing for 7 and this is vital information. Maybe the extra shape information is critical in finding a sharp grand - certainly still possible on the first auction.

In general a bid only needs to be the best choice available, not be correct opposite any hand partner may hold on the auction thus far. Making the best percentage call applies at all levels of the bidding, even the 5-level and 6-level. Your insistence that partner must deny holding Axx before you are allowed to make a void-showing response is consistent but in my opinion not optimal.

Also your suggestion of splintering with 3-card support on the last auction surprises me a great deal.

[mw64ahw]

 Stephen Tu, on 2021-November-20, 00:28, said:

Something like:

---

N/S don't have tools to show void spl. 1s-4h!-?. South think slam is probably pretty good bet though not 100% opposite 2 keycards. But now North presumes void is useful and there you are in slam?
I just don't see how you can tell when the void is useful or not, when partner often has the ace in the suit, and void rather than stiff may not be helping you at all. Now if you can arrange an auction where partner specifically denied any control in that particular suit, then maybe you can tell, but when slam auctions come up it seems all too often I've only shown singleton or void (and sometimes not even that, can only show control in the suit which could be A/K/shortness), and have no idea whether partner is looking at the ace of that suit or not. So basically I can practically never tell useful or not so I routinely do *not* show the void by responding 6 to RKC.

I faced the same challenge when I played RKCB

I'm not sure I'd splinter on that hand without a ♣ control. Better to go via 2NT where you can show the splinter and then cue again below the 5 level to show the void.

Alternatively switch to showing keycards rather than asking for them i.e 4NT from South to show an even number. That way you can re-cue ♥ to show the void.

[Stephen Tu]

 mw64ahw, on 2021-November-20, 06:12, said:

I faced the same challenge when I played RKCB

I'm not sure I'd splinter on that hand without a ♣ control. Better to go via 2NT where you can show the splinter and then cue again below the 5 level to show the void.

??? In standard schemes it's opener who can show a splinter after 1M-2nt, not responder. Now perhaps there is modified scheme involving 2nt for responder to show, but probably only on certain continuations by opener, and if that was in place one might as well have had say 1S-3nt to show a void spl directly, and I already specified that N/S didn't have the tools. This thread is mainly concerning whether North should show void in response to RKC *not* having the ability to show the void below 4 trumps.

Quote

Alternatively switch to showing keycards rather than asking for them i.e 4NT from South to show an even number. That way you can re-cue ♥ to show the void.

This perhaps works for some auctions, but depending on suit you get the awkward situation that North doesn't know if South's even number includes the ace of the void suit or not, and I'm not sure on all continuations North will be able to confirm void, depending on what South's other bids mean and what all of North's continuations mean.

Also this getting far afield from the original question, and won't be available to the vast majority of partnerships.

[Stephen Tu]

 DavidKok, on 2021-November-20, 05:27, said:

I think being certain that the void is useful is sufficient but not necessary to consider the 5NT/6X bid. I was worried you would stick to your guns about your criticism, which is why I specifically mentioned in the third example that this was the last chance to show the void. Maybe partner is probing for 7 and this is vital information. Maybe the extra shape information is critical in finding a sharp grand - certainly still possible on the first auction.

In general a bid only needs to be the best choice available, not be correct opposite any hand partner may hold on the auction thus far. Making the best percentage call applies at all levels of the bidding, even the 5-level and 6-level. Your insistence that partner must deny holding Axx before you are allowed to make a void-showing response is consistent but in my opinion not optimal.

Also your suggestion of splintering with 3-card support on the last auction surprises me a great deal.

On this side of the pond, delayed splinter promising only 3-cd support after making a 2/1 is a common assumption, the idea being that a lot of hands with 4 cd support + spl would have splintered directly on the first round. It has pros and cons; obviously when holding both 4 support and a good side suit it's nicer if the delayed spl guarantees 4 as partner can evaluate a bit more finely. OTOH being forced *not* to splinter when holding 3, means partner will not be able to cooperate intelligently below 4 trumps because he won't know if your cue bid is high card or shortness, and also some of the time you won't even be able to cue your shortness as it might go 1s-2h-2s-3s-3nt!-4c-? because 3nt is artificial (serious 3nt) and you are obligated to show a club control because 4d would deny a club control. Plus someone looking at xxx diamonds is a lot more excited opposite a d splinter than if the cue bid could be based on a diamond holding of Kx or KJx or Axx.

IMO if grand is in the picture with your 3604 hand responder should be grabbing the reins with exclusion, rather than cue bidding diamonds then guessing to show the void over RKC. In my view the hands where opener is taking the reins and responder is too weak to take control are way more likely to have ace of diamonds where the void isn't additive to your trick taking; not holding the ace of diamonds opener would be less likely to be cooperating or bidding rkc rather than signing off or cue-bidding hearts. I think it's way more likely that you drive to 6 - 1 holding the 1 key than you find 7 in this manner, or 6 when it makes because of the void when opener is going to sign off in 5.

[mw64ahw]

 Stephen Tu, on 2021-November-20, 09:03, said:

??? In standard schemes it's opener who can show a splinter after 1M-2nt, not responder. Now perhaps there is modified scheme involving 2nt for responder to show, but probably only on certain continuations by opener, and if that was in place one might as well have had say 1S-3nt to show a void spl directly, and I already specified that N/S didn't have the tools. This thread is mainly concerning whether North should show void in response to RKC *not* having the ability to show the void below 4 trumps.

This perhaps works for some auctions, but depending on suit you get the awkward situation that North doesn't know if South's even number includes the ace of the void suit or not, and I'm not sure on all continuations North will be able to confirm void, depending on what South's other bids mean and what all of North's continuations mean.

Also this getting far afield from the original question, and won't be available to the vast majority of partnerships.

Yep there is the odd situation where you don't get to show the void, but I find showing rather than asking is usually preferable as a response to RKCB can often chew up the bidding space.
There is a natural progression from Blackwood to RKCB to Turbo to Kickbo and in general if you find one tool restrictive then look at using another. The comments above cover most points w.r.t. to the original question

My 1M-2NT approach is non-standard and a two-way conversation rather than either partner being captain, but in this case if you reserve the bids above 3M for Italian cues and inviting slam then either player can initiate.