Posted 2015-June-20, 07:17
Traditional bidding methods in a non-strong club method, in NA, require a 2S rebid over partner's 2/1 red suit response. Most 2/1 players use the same treatment, although some do not and consider showing pattern to be more important.
I am one of those who require about an ace more than a reasonable minimum opening bid for a 3C rebid.
If playing standard American, where a 2/1 response could be a 10 count, the reason for the extra value requirement is that it is normal for 3C to be forcing to game, and thus one has to have significant extras, in order to force to game opposite a potentially misfitting 10 count.
It has to be gf since there is so little bidding space for suit agreement. I leave it to the reader to figure out the reasoning here.
When playing 2/1 GF methods, the need to have extras in order to create the gf are irrelevant, since responder has created a force already, which is why some do not promise extras.
However, one of the weaknesses of 2/1 GF is the difficulties that arise when both players have about 16 hcp and the partnership is in the slam zone. 16 isn't enough for responder to push beyond game, given that opener could have, say, 11 or so. So over a 3C rebid that is merely shape-showing, responder, with extras but not a monster, has to just bid game all too often. Opener, with extras, cannot tell if responder has a minimum or extras, so is facing the same problem.
Using 3C to show significant extras with opener makes it are for responder, with a good hand, to push beyond game.
Btw, while the modern method is, for most, to open 1S on these hands, there are still some players who think that 1C is better on hands that cannot afford to rebid 3C. I play with one of these players, a multiple national champion. I don't like the style, but in fairness, it seems to work well.
'one of the great markers of the advance of human kindness is the howls you will hear from the Men of God' Johann Hari