[straube]

Playing 2/1

1H-1S, 3D-3H, 4C

Does 4C show a control in support of hearts or does it show 0-5-4-4 or...?

[PrecisionL]

4♣ shows a control in ♣ and usually denies a ♠ control, because 3♥ agrees ♥s.

[Stephen Tu]

To me it is shape because 3h shouldn't guarantee fit at all (prob most people expect doubleton, but I kind of agree Steve Robinson who in Washington Std suggests singleton and opener should clarify.)

I kind of hate jump shift auctions in std, no real stds, most books gloss over them, not much room to show everything you'd want. I guess that's a reason for strong club, gazzilli, etc.

[The_Badger]

The responder is only showing preference with 3♥, I feel, not actually agreeing them as a trump suit. I personally can only see 4♣ as a cue bid as opener has a massive hand, just a shade light from a 2♣ opener.

[Tramticket]

Cue-bid, showing a control, for me too.

[Zelandakh]

First of all, 3♥ should be a grope rather than showing a guaranteed heart fit. That said, I have a generic rule that the 4th suit at the 4 level is a (general) slam try in the last bid suit and this is what I think 4♣ should be here. With no fit and club "stuff" we would bid 3NT; with no fit and spade stuff, 3♠. 4♦ would be natural showing a big 2-suiter. That leaves a slam try in hearts as an awkward hand if 4♣ is not available for it.

The main alternative usage that I am aware of is in terms of choice of games. I seem to recall that Andy (gnasher) is a fan of this approach, though I am not sure if advocates of the idea would play it on this specific auction. To my mind, if you want partner to choose between a major suit game you start with 3♠; between red suit games, 4♦. The issue of splitting up your range for 6-4 and one-suited hands is less easy to solve and therefore seems to me to be preferable.