Notation Systems

A core idea in Keyflow: the same music can be written three ways, and they're fully interchangeable. Everything after the root — quality, sevenths, extensions, alterations, slash bass (see Chords) — works identically in all three. You only choose how to spell the root.

Use whichever fits the chart — letter names for a fixed-key lead sheet, numbers for a transposable worship/Nashville chart, Roman numerals for analysis or classical feel.

Those same four bars, engraved straight from a ```kf block:

Write it in numbers instead and it's the same music as scale degrees:

Letter names

Absolute pitch. The root is a note A–G with an optional accidental, and the quality is written out explicitly:

C    F#    Bb    Am    Cmaj7    F#m7b5

Letter names don't depend on the key — C is always C.

Nashville numbers

The root is a scale degree 1–7, relative to the song's key. A bare number automatically takes the key's diatonic quality — you don't write the m. In a major key 1 2 3 4 5 6 7 gives:

So 2 is the ii chord (minor) — no need to write 2m. Minor keys get their own diatonic qualities (in A minor, 1 is Am, 2 is B°). Sevenths and extensions stack on the implied triad: 2:7 is ii m7 (Dm7), 5:7 is V7 (G7).

And because the chart stores degrees, the same 1 4 5 is C–F–G in C and G–C–D in G — that's the point of the number system: the progression, independent of key.

Overriding the quality

• ! before a number is literal — it drops the key association, so a bare !2 is a plain major triad (D in C).
• An explicit quality overrides the diatonic one: 2M / 2Major / 2:maj for major, 2m for minor, plus 2dim, 2aug, 2sus4, …

So 2 = Dm (diatonic), 2M = D (forced major), !2 = D (literal), 2m = Dm (explicit).

Roman numerals

Also a scale degree relative to the key, but case carries the quality — uppercase is major, lowercase is minor:

I  ii  iii  IV  V  vi  vii      →  I, iim, iiim, IV, V, vim, viim

You can still add explicit descriptors on top: Imaj7, V7, iim7.

Roman numerals also unlock two analyst's tools, both covered on the Chords page: secondary chords with / (V/V is "five of five"), and inversions with ^ (V^65 is a first-inversion dominant 7th).

Readability: the : separator

When a number or numeral is followed by a quality that starts with a digit, the two runs of digits can be hard to read — is 17 "degree 1, seventh" or the number seventeen? Optionally put a colon between the root and the quality:

1:7      4:maj9      2:m7      5:9

It's purely for readability and carries no meaning — 1:7 and 17 parse identically, as do 4:maj9 and 4maj9. The colon works on all three systems — numbers (4:maj9), Roman numerals (V:7, i:m7), and letter names (C:7) — though it matters most for numbers.

Good practice: write the :. 1:7 reads cleanly; 17 is correct but easy to misread. (A future editor will insert the : for you automatically.)

Relative to the key

Both number-based systems resolve against the key set in the header (#C, #Gm, …). Because the chart stores degrees rather than fixed pitches, transposing a Nashville or Roman chart is just changing the key in the header — every chord follows.

Letter names are the opposite: fixed pitches that ignore the key.

Accidentals and borrowed chords

Put # (sharp) or b (flat) before a degree or numeral to raise or lower it — exactly how you write a borrowed or chromatic chord:

1  b3  4  b7        (numbers)   ♭3 and ♭7 borrowed
I  bIII  IV  bVII   (Roman)     ♭III and ♭VII borrowed
1  #4  5            sharpened 4th

Since almost no one can type a real ♭ glyph, Keyflow treats the plain letter b as a flat in these positions.

The b7 question

That creates one genuine ambiguity: b7 could mean the note B with a 7th (B7), or the flat-7 degree (♭7). Keyflow resolves it from the surrounding notation system:

The current line decides first; if it can't tell, the rest of the chart does; failing that it's read as the note B. Only b5/b6/b7 are ever ambiguous — b9 and up can only be the note B (degrees stop at 7), and any #-prefixed number is always a degree.

Mixing systems

You can borrow a Roman or number chord inside a letter chart — bVII and #IV are unambiguous, so Bb bVII Eb reads the bVII as the flat-7 degree while the rest stay letter names.

The same for melody

The naming carries over to melody too — melody notes are written as letter names or scale-degree numbers, the same choice you make for a chord root. (Roman numerals name chords, not single notes.) See the Melody page.

What's next

• Rhythm — how long each chord lasts, and why a bare chord fills a whole bar.