[CGMthrowaway]

OK let me suggest something to meet you halfway. As someone who is fluent/sight reading/ singing etc and can "hear" harmony and/or "read" it on a page of regular notes (lines and spaces and intervals all you really need, but to your point requires experience), something that would be far more interesting and useful to me, rather than color-coding solfege, would be something more along these lines:

Color code each chord by its diatonic value (e.g. in a I chord every note in the triad is red, in a IV chord every note in the triad is blue) and then highlight the extended notes as well (e.g. add 9 is yellow, add 11 is green)

That is something that MIGHT be interesting to me (personally - I know I am not your audience). But even thinking it through this technique sort of washes out the interesting bits of substitution/interpretation etc that you can find because you are committing to interpreting a chord with a single root

[vitaly-pavlenko]

Yeah, I see your point. You want same alterations on different Roman numerals to look the same. (In my current system b9 over I and b9 over V look different.)

I briefly explored this appoach: https://rawl.vercel.app/edit?a=beethoven_op10no1mov1 (Although it was a mess.)

In current Rawl terms I call it "annotate modulation at every chord".

Back in the days I thought it's better.

It turned out that:

- You need to do tedious annotation. So you can only work with classical repertoire datasets like https://github.com/MarkGotham/When-in-Rome

- Worse even, you need to look at two places simultaneously: to the score and to the string of Roman numerals

- And worse still, all chords then look the same. The score itself becomes bland. Most of the time, if you aren't deep inside the jazz repertoire, there isn't that many alterations. So you'd mostly see the same four colors - root, minor third, major third, perfect fifth.

- And, as evident in Mozart-Beethoven repertoire, you need to decide what to do with fully diminished chords. Because they sorta don't have a root, acoustically.

[CGMthrowaway]

Thanks for the example. Devils advocate:

> You need to do tedious annotation. Worse even, you need to look at two places simultaneously: to the score and to the string of Roman numerals

The more work it takes to create your notation, the more useful information it contains. Developer-user tradeoff

> And worse still, all chords then look the same. The score itself becomes bland. Most of the time, if you aren't deep inside the jazz repertoire, there isn't that many alterations. So you'd mostly see the same four colors - root, minor third, major third, perfect fifth.

Isn't the same true for your current method? Only there are more colors of the rainbow to distract you from how bland it is :)