Nashville chording, used by studio musicians everywhere, is a chord notation based on the keyboard notenames. Noshville chording is something like 1-2-3 solfeggio, in that the note names have pattern meanings only, regardless of key or key signature. Flatted and sharped notes have letter names, making b and # signs unneeded.
Here you see a horizontal fret-squiggle with chord root names laid along; low-high is left-right, as on a keyboard:
2 3 X Y Z 1 2 3 X Y Z
L M 4 5 6 7 L M 4 5 6 7
You’ll note that letternames might happen to correspond in pattern to a keyboard’s black keytops; numbers could correspond to white keytops. (Opposite though, on many harpsichords) However, this correspondence is not fixed.
The freed-up correspondence is crucial to the usefulness of Noshville. The same may be said of solfeggio in its do-re-mi and FaSoLa (shape-note) forms, the ni-pa-vou-gha-dhi-ke-zo-ni (Byzantine) names, and other such note alphabets.
For early earwork on the domino-tonic relation we can use “Do you see what I see?” or the opening theme of R.Strauss: Also Sprach Zarathustra (World Riddle Theme — just first three notes):
Tonic Dominant Tonic Dominant
Do you see what I see?
1 1 5 5 1 5 (key-free Noshville)
C C G G C G (C major Nashville)
Bb Bb F F Bb F (Bb major Nashville)
With Noshville chord names in hand and some practice drawing a vertical squiggle, you might take a standard workbook in Nashville chording and follow it more easily through the intricacies of major-minor-diminished-augmented chords, 7th, added 9th, suspensions, slash chords and so forth.
In your composing, you might delay the decision of what key to chord in by using Noshville root names with all the ancillary marks such as minor, 7, diminished etc. Your band might come to prefer Noshville even after settling on performance key decisions.