[kemperb]

Free, on 2011-November-08, 08:36, said:

In theory: yes
In practice: no, perhaps a small edge.

It seems to me that in theory, whatever declarer's best play is against standard carding, he can make the inverse play against upside down. There should be the same (mirrored) scenarios that win with one as with the other, so there should be no edge with either one.

I agree that in practice, declarer will tend to be prepared to card optimally against standard carding, and will thus be suboptimal against UDCA, giving it an edge.

[phil_20686]

kemperb, on 2011-November-09, 19:09, said:

It seems to me that in theory, whatever declarer's best play is against standard carding, he can make the inverse play against upside down. There should be the same (mirrored) scenarios that win with one as with the other, so there should be no edge with either one.

I agree that in practice, declarer will tend to be prepared to card optimally against standard carding, and will thus be suboptimal against UDCA, giving it an edge.

These situations are symettric, but there are others where it is not:

Partner leads the K from AK or AKQ and you have Qx/Jx - occasionally you want to preserve the J as an entry, to do this in std you must lie whereas it is auto in reverse.

You hold QTx and partner leads A or K, now you automatically unblock your pip while giving correct count.