[fromageGB]

 relknes, on 2011-December-15, 11:02, said:

So what would you do if you have, say, diamonds and hearts, but not clubs?

This is where it doesn't work, when both parties are unlimited by the bidding. However, often somebody makes a bid which limits the hand to a range of values. In that case, it is easy.

Example : 1♠ 3♦ (Bergen 4 card support bid, defined strength/HCP range) 3NT.
We play non-serious (or frivolous) 3NT, where it is 3NT over spades, but 3♠ over hearts. So when both sides are undefined in strength, a serious hand would bypass that bid and make a cue bid. However, if partner is limited, as in this example, there is absolutely no sense in telling him you, too, are limited; you just sign off in game. So now the 3NT bid becomes a "serious 3NT", which insists on a cue bid sequence. However, this bid denies control in clubs. If you had club control, but not diamonds, you would have bid 4♣, the one beneath the one you want partner to bid. So you can in fact ask for the cheapest.

Most times, in fact, one partner has limited his hand in some way. In a 2 over 1 sequence (the way we play it) opener limits his hand if his initial rebid is no higher than 2M (2NT from responder then asks for shape).

Where both are unlimited, partner has bid 3♠ agreeing trumps in a forcing situation, and we are serious with missing club control, at the moment we just bid as if we have it, and take a risk, if you like, of missing the top 2 tricks in the suit. But this is the only suit with a problem, and we think it worth the definite advantage of always being able to show extra strength (without being unilateral), to enable partner to bid on if he too has extra strength. The "16 points opposite 16" hands (or equivalent) is a bigger problem otherwise.

[Zelandakh]

 relknes, on 2011-December-15, 10:56, said:

I had been planning on using 3NT for one of three things, Serious NT, Frivolous NT, or denying 2 of the top 3 trump. So my next question is: which of the three works best with this style of (anti-)cuebidding?

I play Frivolous with DCBs and think this is the best option. It does mean that with a serious hand and controls in all side suits you either have to either "fake" a cue bid (as you describe) or, more commonly, just bid RKCB.

The example you give is an example of why you need to be a little bit careful with DCBs, and any cue bids for that matter. Your partner should usually give a positive response with a shortage in the cue suit. A singleton diamond opposite your KQ97 is not going to be good news! A simpler solution with a club void, controls in all suits and serious slam interest would be to jump to 5C over 3S as Exclusion.

This is the basic advantage of DCBs in a nutshell - when you have serious interest and all suits controlled you are usually in a position to take control and start asking specific questions. With standard cues you have 2 ways of showing this hand (you can also cue) but no way of showing a serious hand missing a control in a suit below game without forcing to the 5 level without asking for key cards. This is where you need to start bolting on extras like LTTC and a jump to 5M to ask for a specific control. That is fine for experts but the DCB method achieves similar results with simpler rules and is thus perfect for I/A.