[hokum]

1♥-4♦ (splinter)
5♣

Somebody asked me today if 5♣ here is exclusion or a club control. Is there a consensus that exclusion requires a jump?

Thanks

[MrAce]

Control, showing 1st round cl control ( 5 level 1 st round and denying 1st or 2nd round spade control

[Lorne50]

hokum, on 2013-December-20, 22:11, said:

1♥-4♦ (splinter)
5♣

Somebody asked me today if 5♣ here is exclusion or a club control. Is there a consensus that exclusion requires a jump?

Thanks

If you have a slam try ask yourself how often will it be with a void in clubs vs how often a control you want to cue bid? The second is clearly a lot more likely so it does not make sense to play it as exclusion.

[Zelandakh]

Lorne50, on 2013-December-22, 09:15, said:

If you have a slam try ask yourself how often will it be with a void in clubs vs how often a control you want to cue bid? The second is clearly a lot more likely so it does not make sense to play it as exclusion.

This is true but you could perhaps fudge a little bit, say 4♠ = RKCB; 4NT = generic slam try; 5m = void-showing; 5♥ = spade void.

To the OP, the general rule is that XRKCB requires a jump and you need a special agreement with partner (beyond the special agreement of playing XRKCB itself) for non-jumps also to be XRKCB.

[mfa1010]

hokum, on 2013-December-20, 22:11, said:

Is there a consensus that exclusion requires a jump?

Yes I think so absent a specific agreement to the contrary.

[Zelandakh]

Having posted before about XRKCB being a jump, I thought I would come back to this topic and point out where there is perhaps some space for an alternative agreement. Let us take a simple everyday auction, say 1♠ - 3♠; 3NT - 4♦, where 3NT was a general slam try (Frivolous) and 4♦ showed serious slam interest with a control in one minor and not in the other. So it is good to play 4♥ here as some form of Last Train or Asking Bid showing a control in the other minor and focusing on whether partner has a heart control. If we control the responses to that we can achieve XRKCB. For example:

1♠ - 3♠; 3NT - 4♦
==
4♥ = asks for a heart control
... - 4♠ = no ♥ control
... - 4NT = ♥ control and 1 or 4 key cards
... - 5♣ = ♥ control and 0 or 3 key cards
... - 5♦ = ♥ control and 2 or 5 key cards without ♠Q
... - 5♥ = ♥ control and 2 or 5 key cards with ♠Q
4♠ = sign off
4NT = XRKCB (♥ void)
5m = XRKCB (void in m)
5♥ = ♣ void and no ♥ control
5♠ = ♦ void and no ♥ control

or, if you want to avoid the direct key card responses to leave more freedom for a cue auction:

1♠ - 3♠; 3NT - 4♦
==
4♥ = asks for a heart control
... - 4♠ = no ♥ control
... - 4NT = ♥ control
... - ... - 5♣ = RKCB
... - ... - others = control cues
... - 5♣♦♥ = ♥ control and void in suit bid
4♠ = sign off
4NT = RKCB
5♣♦♥ = XRKCB (void in suit bid)

Now both of these ideas have obvious disadvantages over a more standard approach and I am not claiming some breakthrough in slam bidding methods. There are also advantages though and I am confident that this kind of structure would make non-jump XRKCB (NJXR) playable in many (but not all) auctions. Indeed, it turns out that the specific auction in the OP (1♥ - 4♦) is one of those where you really do have to give up far too much to make NJXR workable. The issue here is that there is no space to identify controls below game level and, crucially, no forcing call available to multiply and maximise the sequences available.

Anyway, it turns out BBF has a resident expert in the bidding theory of slam auctions, particular cue bidding. So here's a call to Ken - do you have anything here? I would be surprised (impressed) if you have a scheme for the 1♥ - 4♦ case but perhaps you have something more general that is a little better optimised than what I have posted here.

[fromageGB]

I don't think you can do this by consensus, because to play exclusion you need to discuss it. I don't really see the point of it being a cue as there is no room for responder to bid anything. I play this as exclusion, surely much more useful.