[kgr]

SAYC (you have not discussed if a direct 2♠ would be strong or weak):
bidding goes:
1♣-(1♦)-1♠-(2♦)
P-(P)-3♠
or
1♣-(1♦)-1♠-(P)
1NT-(2♦)-3♠

Is 3♠ in SAYC forcing or limit? Do you prefer to play it forcing or limit?

My thoughts:
Without the 2♦ bid it could go:
1♣-(1♦)-1♠-(P)
1NT-(P)-2♦-(P)
2NT-(P)-3♠
Showing a GF with 6-card ♠

but with the 2♦ bid it will go:

1♣-(1♦)-1♠-(P)
1NT-(2♦)-3♦-(P)
3NT-(P)-..
and you will have to bid 4♠ to show a 6-card.

[temp3600]

The SAYC booklet has this guideline for competitive bidding : "Bids mean the same things they meant without the intervening bid". So in the auction
1♣-(1♦)-1♠-(P)
1NT-(2♦)-3♠,
3♠ should be invitational.

The booklet doesn't say anything about balancing, but I would be very surprised if 3♠ wasn't invitational in the sequence
1♣-(1♦)-1♠-(2♦)
P-(P)-3♠.
It eases the load on the memory, plus responder is likely to have about the same strength in both sequences.

There is also X by responder at his second call to consider. Some people use it to show extras without a clear bid (I think it is described as an 'action double'), in which case it gives additional sequences and allows to differentiate more precisely between types of hands :
1♣-(1♦)-1♠-(P)
1NT-(2♦)-3♠

1♣-(1♦)-1♠-(P)
1NT-(2♦)-X-(P)
2♥-(P)-2/3♠

1♣-(1♦)-1♠-(P)
1NT-(2♦)-3♦-(P)
3♥-(P)-3♠
for example. Some discussion is obviously needed for the partnership here.
Others prefer to have the punitive X still available.

I hope this helps.

[helene_t]

I think it should be forcing since a direct 2♠ should be weak. But that isn't SAYC, I know.

[cherdano]

For me, all these bids are invitational.

Helene's argument makes sense if you play the jump to 2♠ as constructively weak (4-8), but I guess standard is more like 0-6, in the US at least.

Arend