[Hanoi5]

♠
♥KTxx
♦KQJ98
♣K954

All white, partner opens 1♠ and jumps to 3♠ over 2♦, is it obvious?

1♠-2♦
3♠-?

What would a 4 lvl bid in a new suit mean? What about 4♦?

[Fluffy]

I think most experts play 3♠ as WE ARE GONNA PLAY IN SPADES NO MATTER WHAT.

Opposite that I think I 3NT is best description, minimum and zero slam interest, but 4♠ is a good alternative (or the only one if playing serious/non serious 3NT)

If 3♠ just show extras with decent 6 cards again 3NT is obvious

[aguahombre]

The specialized 3S rebids do not apply here. It must just show extra values and a 6-card suit. The solid-suit/minimum thing used by 2/1 players is workable, but the responding hand is not a game force over a 1♠ opening. So, we assume a standard card and try 3NT.

[the hog]

3NT is obvious to me.

[Codo]

For your question: 4 of a suit is a control with SI in spades.
I would not try it with this hand, I would bid 3 NT to show my shortness.

[Quantumcat]

Fluffy, on 2012-September-15, 19:36, said:

I think most experts play 3♠ as WE ARE GONNA PLAY IN SPADES NO MATTER WHAT.

I think this is standard if playing 2/1, expert or not.
Example hand:
♠KQJT983 ♥AQ2 ♦4 ♣Q2
Doesn't need extras, just a good enough spade suit to play opposite a singleton or void.

Fluffy, on 2012-September-15, 19:36, said:

If 3♠ just show extras with decent 6 cards again 3NT is obvious

I think this is standard when playing Standard.

[PhilKing]

In my partnership, 3♠ promises a suit playable for one loser opposite a void and extras.

Over that:

4♠ = go away
4♣/♥ = cue in decent hand
4♦ = natural - not a cue bid
3NT = Rodwell (min but not unsuitable)

So here I would bid Four Spades and reach for my scorecard.