CDH Convention

[bensam]

The CDH ( Club-Diamond-Heart) convention allows the responder of a 2 Club opening bid to inform partner that despite a bust hand responder has a void and ,thus, at least one 5 long cards suit. If a FIT is found a slam is possible despite the bust hand !

 

When the CDH convention is used 2 Diamond Waiting is replaced by 2 Spades Waiting ( must be alerted ). The 2 Heart bid indicating a busted hand without a void remains the same.

 

Example:

North opens 2 Club ©

South response is 2 Diamonds (D). That bid must be alerted by North indicating a bust hand with one or two voids.

North bids artificial 2(H) to be alerted by South as ''Waiting artificial''.

 

South then informs North of is void by a transfer ( must be alerted as transfer).

North completes the transfer

South then bids is void suit.

 

North thereafter has enough information to conclude the bidding. With a FIT in South's long suit a slam should be considered. Asking for control is not needed since North already knows that South has a bust hand.

Author of the CDH convention : Ben Samson

[manudude03]

That seems really bad if the 2C opener has hearts. After it goes 2C-2S-3H, it doesn't leave much room at all to try and sort out both the strain and the level. Sure it probably gains when responder does have a bust hand with a void, but how often does that happen? If you are going to make something like that, it is surely more logical to make the 2S response as showing some void since it will be fairly well defined and so the space doesn't matter so much.

 

Also, you seem to imply that south shows the void twice for some reason.

[wank]

this is obviously a wind-up. i've not seen philg recently.

[Phil]

Hi Ben.

 

This is a great place for innovation and you'll get some good feedback.

 

However, you'll find out soon enough that you are using the two cheapest calls for meanings that occur probably less than 1% of the time and that's too high a price. WHEN the bidding starts 2C 2S as it will most of the time you've squandered valuable space as well as frequently wrong siding spades.

[fromageGB]

My feeling on the 2♣ issue is that it is when responder has hcp values of some sort then you need all the space to explore both the strain and the level, while when responder has nothing it is simply a question of strain. Opener decides level.

 

Therefore the positive response - waiting response if you like - should be 2♦, and the negatives can bid higher. If you wanted a separation between void or not when bust, it would be better to swap your diamonds and spades bids. Rather than a CDH convention, a CSH?

 

However, rather than that, it may be better for responder to simply bid his void, if spades, as this will probably not be the trump suit. How about 2♣ ...

2♦ = positive

2♥ = negative without void

2♠ = negative with spade void

2NT = negative with other void.

Over the 2NT, opener may bid his suit and responder bid the next if opener has hit his void.

[1eyedjack]

I am quite in favour of getting shortages across without necessarily distinguishing early in the auction between singleton and void. Values opposite either tend to be wasted to broadly the same extent, for slam investigation in a suit strain, and likewise for strain investigation some tolerance for other suits can (in some context) be assumed with a modicum of safety. Distinguishing between singleton and void can be important, but can be clarified later once that importance has been established, which will not be every time, not least (and certainly not only) because the strong hand is reasonably likely to hold the Ace opposite the shortage, where the importance of a void is lessened.

[Zelandakh]

Hello bensam and welcome to the BBO forums. I took the liberty of looking up your playing record and can see from this that you are still fairly new to the game in terms of development. There are some good reasons why this scheme of responses is not good, which I daresay you will pick up after a while if you spend some time on these forums.

 

As a general principle, we want to maximise bidding space when it is our hand, which it should be when we open 2♣. As such, making it so that our first natural call is at the 3 level most of the time is poor design. That said, you might also care to look up some old threads about when to open a hand 2♣. The only example I could find from you in the last month was ♠- ♥KQ7653 ♦AK6543 ♣T. I am reasonably confident that the majority of BBF posters would not have chosen a 2♣ opening on this hand, so it might help your bridge to start from the basics before trying to create something of this nature.

[Vampyr]

My feeling on the 2♣ issue is that it is when responder has hcp values of some sort then you need all the space to explore both the strain and the level, while when responder has nothing it is simply a question of strain. Opener decides level.

 

Therefore the positive response - waiting response if you like - should be 2♦, and the negatives can bid higher. If you wanted a separation between void or not when bust, it would be better to swap your diamonds and spades bids. Rather than a CDH convention, a CSH?

 

However, rather than that, it may be better for responder to simply bid his void, if spades, as this will probably not be the trump suit. How about 2♣ ...

2♦ = positive

2♥ = negative without void

2♠ = negative with spade void

2NT = negative with other void.

Over the 2NT, opener may bid his suit and responder bid the next if opener has hit his void.

 

I am not sure that responder's occupying the 2NT spot is likely to be successful. Especially when you will have all sorts of tools available over opener's natural 2NT.

[fromageGB]

I am not sure that responder's occupying the 2NT spot is likely to be successful. Especially when you will have all sorts of tools available over opener's natural 2NT.

A fair point on the face of it, but if opener has a natural 2NT rebid then you will not be playing in NT. I don't think the idea of showing a void is likely to be successful anyhow, but I would prefer this method to that of CDH.