1. Introduction to the Nashville Number System
What is the Nashville Number System?
The Nashville Number System (NNS) is a method of transcribing music by denoting chords according to their scale degree rather than by their letter name. Developed in the late 1950s by Neal Matthews Jr. of the Jordanaires, the system revolutionized how session musicians in Nashville could quickly learn, transpose, and perform songs.
Why Use Numbers Instead of Letters?
The primary advantage of the Nashville Number System is instant transposition. When you write a song progression as 1–4–5–1 instead of C–F–G–C, any musician can immediately play it in any key by simply knowing what key you're in.
Example:
- In key of C: 1–4–5–1 = C–F–G–C
- In key of G: 1–4–5–1 = G–C–D–G
- In key of D: 1–4–5–1 = D–G–A–D
The progression remains the same; only the starting pitch changes.
Key Assumptions
The Nashville Number System can work in both major and minor keys. Unless otherwise noted, these are the standard assumptions:
For Major Keys:
- Numbers without modification represent major triads (1, 4, 5)
- Numbers 2, 3, and 6 are assumed minor (2-, 3-, 6-)
- Number 7 is assumed diminished (7°)
For Minor Keys:
- When the chart indicates a minor key (e.g., "Key: Am"), the 1 chord is minor
- Numbers represent the natural minor scale unless otherwise marked
- Common to see raised 7th (leading tone) in minor keys
General Conventions:
- Nashville numbers are assigned from the major scale of the current key center, even when the song uses modal mixture or borrowed chords.
- There is no single universal NNS standard; chart writers may use different symbols and layout conventions.
- The song key, time signature, tempo, and feel are noted at the beginning of the chart
- Key signatures with sharps and flats are enharmonically equivalent (C♯ = D♭) but notated according to the key.
- NNS Pro intentionally avoids double sharps and double flats in display and uses enharmonic equivalents for readability, though various musicians may have different preferences on this topic.