[Mbodell]

Playing normalish 2/1 with immediate invitational jumps to the 3 level (so 1♥-P-3♣ would be inv, (8+)9-11, with 6+♣ and 2 or fewer ♥), what is 4♣ in the following auction (all white MP if it matters):

1♥-P-1NT(forcing)-P
3♦-P-4♣?

[mike777]

Mbodell, on 2013-August-02, 22:23, said:

Playing normalish 2/1 with immediate invitational jumps to the 3 level (so 1♥-P-3♣ would be inv, (8+)9-11, with 6+♣ and 2 or fewer ♥), what is 4♣ in the following auction (all white MP if it matters):

1♥-P-1NT(forcing)-P
3♦-P-4♣?

cue in support of d given OP. deny spade cue. often extra shape.

xxx...x....KJxxx....AQxx

could be more.

[jallerton]

Responder might have long clubs without support for diamonds or Responder might have a hand wishing to cue in support of clubs. The latter hand can start with 4♦ and then cue bid 5♣ on the next round if appropriate. The former hand would be unbiddable if 4♣ did not show clubs, so 4♣ should be natural in the absence of an agreement to the contrary.

[Thiros]

We're in a game force, and our system has already eliminated the 8-11 point hand with 6-7 clubs. Therefore, this 4♣ bid should be natural and show uncommon club length, 7 or 8 cards, and 5-7 HCP most or all in our long suit.

[Fluffy]

3♥ = ♥. 3♠ = ♦, 4♣ = ♣, 3NT = NT

[P_Marlowe]

Hi,

#1 you have a slam try for diamonds: 4D
#2 you have a slam try for hearts: 3H / 4H, I guess 3H being the stronger variant.
#3 you know, how frequent you play Gerber, I dont play Gerber.

Basically this leaves a weak hand with lots of clubs, but I dont think there is a standard
meaning.

With kind regards
Marlowe

[TWO4BRIDGE]

My take ( definitely not standard ) :
3H = minimal hand and support could be as little as 2 cards.
4H = limit w/ 3 cards; a hand that would have jumped to 3H over a minimum rebid of say 2D.
3S = some sort of try for 3NT .
3NT = stop(s) in both unbid; NT not the best place for these types of auctions unless Opener has a running suit.

That leaves the following 4-level rebids as RKC-"Showing" , agreeing ♦ :
4C = 0/3
4D = 1/4
4S = 2 - ♦Q
4NT = 2 + ♦Q

Now Opener is in a good position to either place the contract or make another "ask" .

- - - - - - - - - - - - - - - - - - - - - - - - - - -- - -- - -- - -
A Zelandakh improvement:
"I think you can improve that Don. For example you could play that 4♦ shows exactly 4 cards Diam and 4♣/4♠/4NT/5♣ show 5 card support + key cards. "