[awm]

A bit of expert perspective on carding...

When deciding how to signal, it is worth considering what line of defense partner is likely to adopt. Typically given an encouraging signal, partner plays the suit she lead again at next opportunity. Given a discouraging signal, partner typically plays some other suit. Often (but not always) you can figure out what suit this will be by considering dummy and the bidding.

It tends to be quite costly for partner to be first to break a suit where I have no help (barring a strong sequence or other holding where partner can always figure out to lead the suit on her own). It follows that if I'm sure that a discouraging signal will convince partner to make such a disastrous shift, I should encourage. This makes encouraging more of a "neutral action" -- if I have nothing at all it's generally better to encourage since the damage in the opening lead suit is already done.

The one remaining point is that sometimes I cannot tell which suit partner will play if I discourage. Some experts prefer to just use their experience here and then blame partner if it doesn't work! However those of us who like more formal agreements gravitate to obvious shift. It's important that the formal rules match expert experience as much as possible (else you get the situation where it is "obvious" to shift to a certain suit yet you can never get that shift!)

[Shugart23]

thanks. This is much clearer now