Six Sigma seeks to improve the quality of process outputs by identifying and removing the causes of defects. IT is an industry that is doing well if it gets One Sigma - isn't a methodology named and oriented at Six Sigma a little ambitious.
The very mystical terms "Six Sigma", "Black Belt" have the air of those other consulting buzz-words du-jour - TQM, BRP, Y2K. How many time are people going to be fooled by these things?
I suspect that "Black Belt" is an accidentally appropriate terms. It martial arts it really means someone who has learned the fundamentals. And for most of these "arts" real world martial (fighting in war, or in real life) efficacy is not their real orientation - they are arts, sports, exercises, etc. If one wanted to achieve martial there far faster and easier ways.
My issues is not with desire to improve outcomes by thinking how things are done and working out how they could done better. I am also sure that there are many techniques. It is with vodoo fashion branding the consulting industry applies - I object to. when most of it simply comes down to thinking carefully.