At a tournament this weekend, I was talking with someone about ZO settings, and I said I was using B1. He said he was using A3, and then said something like "which is almost B1 anyhow." I didn't think much of it at the time, but that's wrong -- isn't it? I think it reflects the myth that the settings are just 9 stops along one line, i.e. A1, A2, A3, B1, B2, B3, C1, C2, C3. But in fact (according to information gathered here and linked from here), the letter and the number are two independent parameters. So B1 vs. A3 is almost as different as you can get (with only C1/A3 and A1/C3 being further apart). It would be much more accurate, when considering similarity, to think of it as a square: A1 A2 A3 B1 B2 B3 C1 C2 C3 Right?? And I don't think this is a purely academic consideration, as it effects how one should experiment in finding a setting. If B1 seems pretty good, but you're still experimenting (as I am), then the ones to try out would be the neighbors: A1, C1, and B2. Similarly, if you want to get a feel for the range of parameters, you'd want to try the corners: A1, A3, C1, C3. If you (incorrectly) think of it as a line, it will be harder to figure out what to try and how to understand your results. So let's spread the truth on this! (Unless this isn't the truth...)