Carl D. Sorensen wrote: That look pretty good, I disagree here and there (some small some larger objections), but I like the fact that he includes the sometimes-fighting-against-each-other-names (for instance some people can spend hours discussing why "C5" is correct and "C(omit3)" is not). I think a complete, consistent definition of what names IMO are considered good practice in Europe, would be the most useful to you. Did you consider implementing several parallel naming conventions? I think that would be best, since different people insist on a certain name for a chord, and those "certain names" often fall in sets that seems to be geographically oriented. What do you mean by "naming"? There's something fishy in his argumentation for C,D,G = Csus2. I think he is wrong there. IMHO that's nonsense, sorry. Chord symbols don't translate into voicings like that. Here and there there are rules, but that more like good practices and people like Monk and Ellington breaks them all the time. I actually don't see where any of the links you mentions claim anything about the 5th being above or below the root? Actually that was one of the things I found odd the last time I looked at lilypond (maybe it has changed): To get it to write the chord cymbol C13 I had to write a big, fat chord that spelled like "C, E, G, Bb, D, F, A" and sounds like... not so nice, I'm sorry. Nobody would ever voice a C13 like that! A simple voicing would be C, E, Bb, D, A (has to have C one octave below middle C) but there are endless other possibilities. As already mentioned, I think that a couple of well defined "systems" or "logics" for chord names should be included, one fairly well defined one that even has it's own name is Berklee, one that I'm not too familiar with unfortunately.