...between my regular partner and I. This one should be easy for you guys. We play mostly offline and in easygoing non-sanctioned duplicate events, so I suppose this problem doesn't come up that often. The question, briefly, is: Is any deviation in bidding from what appears on the convention card grounds for a CD call and possible penalty? If I open a 4 card major but convention card says 5 card majors, am I subject to CD call? If I decide I need to open 1NT with 18 points, and our convention card says 15-17 am I subject to a CD call? When my partner alerts "15-17" and I don't "correct" her, am I subject to a CD call? If we play standard SAYC, and I have a complete mental breakdown and open 3S with 18 points and 5 spades (resulting in either a terrific or awful outcome), am I subject to a CD call? My partner claims that anytime you don't strictly follow your convention card, you are subject to a challenge and penalty. It seems to me that, presuming that you and your partner have no previous hidden agreements (and are therefore cheating), you are free to make whatever cockamamy bid you want, regardless of what cards you're holding, as long as there are no hidden agreements and your partner is as confused as everyone else. If this is not true, then it seems to me that the bidding process is based not on skill and a sense of context, but instead on who has the best memory to successfully navigate through complex, byzantine bidding systems. -- Mike