[Antoine Fourrière]

After, say,
1S 2D
2H/2S/2N,
it looks easy to play 3C as a retransfer with both
xx xx AQJxxx QTx
and
Ax xx AKJxxxxx Jx,
and to report the 3C bid (more or less natural over 2S and 2N, fourth suit over 2H) at 3D.

Hence, there is no real need of a jump shift in diamonds, at least if you play 1N forcing.

But with clubs, it is not so easy, so I think one of the aforementioned types (preferably the latter, since you may want to invite with six clubs and four cards in the other major) should answer 3C, or 3D if 3C (Jacoby?, minisplinter? ) is not available. If the latter, that jump shift in clubs needn't show such a strong suit, only a hand which wants to bid and rebid clubs in a forcing situation.

[luke warm]

i don't follow your question.. is it a jump shift after 1H or 1S to 3C or is it 1M : 2C : 2H : 4C ?

if it's the first, 3C is a fit jump (to me)...