Just suggestion on how to improve the tool.
- Nashville is fine, a lot of other sources used Roman, no big deal.
+ The key button at the bottom should let you change keys. (Mine does not)
+ a video button with some basic of chord progression (common progressions, passing chords, importance of Tonic Sub-tonic etc.)
+ passing chord suggestions.
+ Next chord (comes from statistics)
+ how to borrow chords.

Borrowed chords are chords borrowed from other modes or keys. They are used to provide harmonic variety through contrasting scale forms. The most common borrowed chords are the ii chord from the parallel minor key and the IV chord from the parallel major key. The ii chord is often a half-diminished seventh chord and the IV chord is often a major seventh chord. Borrowed chords progress in the same manner as the diatonic chords they replace except for ♭ VI, which progresses to V (7).

The notation V/V means “the dominant of the dominant” and VI/V means "the submediant of the dominant"2. These are examples of secondary dominant chords which are borrowed chords from another key.


Studio One (latest version), Win 11 23H2 , i9 -10940X 3.3 GHz, 32GB Mem, a 4K 40" monitor, PreSonus Studio Live III Console as interface/controller. secondarily test on Reaper, Cakewalk, and S1 on Surface Pro 3 Win 10 (latest versions).