I don't have the Klaus Ignaztek book to reference. At this point I'd be surprised if Lilypond is incorrectly rendering chordnames from that system given how long it has been in place within Lilypond.
Is the complaint correct that those chordnames are rendered wrongly *within the context of the Ignaztek system?* If so, that should be corrected; but is the underlying issue the preference of the user being different from Ignaztek or perhaps one of how the chord is being spelled in the input? As in #6279, when one of the extension voices is omitted in the spelling of the chord such as leaving out the 7th or the 9th with another note above such as the 11th, the rendering is sometimes not what the user expected. Lilypond's logic of the spelling may be different than what the user intuits. I have run into this a number of times and thankfully someone here has been able to sort me out with the effective spelling. I have an extensively modified version of the pop-chords.ly exceptions file that I use to render chordnames to my preferences, which are conditioned by the Real Book style. > On Jan 8, 2026, at 11:37 PM, Werner LEMBERG <[email protected]> wrote: > > Jazz folks, > > > please have a look at issue > > https://gitlab.com/lilypond/lilypond/-/issues/6279 > > and comment. My knowledge of using Jazz chord notation is of > theoretical nature only... > > > Werner
