Roman Numeral Analysis
A chord chart in names tells you what to play. A chart in numerals tells you what is happening. Take two songs, one going C, G, Am, F and one going Eb, Bb, Cm, Ab. On paper they share nothing. In numerals they are the same four chords.
- 7 numerals
- any key
- function instead of name
Where you run into this
- Every style
- Analysis
- Songwriting
- Session playing
In short
The gain is double. First, the analysis stays valid in every key, so transposing becomes arithmetic rather than guesswork and an idea you write down today still works years later in whatever key you need. Second, you start seeing patterns that chord names hide. Once everything is on the same denominator, it becomes obvious how much of popular music runs on a handful of shapes.
This is the moment music stops being a list of names. Uppercase for major, lowercase for minor, a small circle for diminished, and a flat sign for a degree lowered from what the key would give you.
How it works
The most common mistake is worth stating plainly. In A minor, writing bIII for a C chord does not mean flat relative to the minor scale, where that third degree is entirely normal. It is measured against A major, the parallel major: there the third degree would be C sharp, so here it is bIII. The same goes for bVI and bVII. Second pitfall: V/vi in classical analysis means the dominant of the sixth degree, while a slash in pop notation means a bass note. Read the context.
Where you run into this
- A chord chart in numerals that works for a singer in any key
- Two songs that turn out to be identical once you write them as numerals
- A jazz lead sheet where the numerals reveal a chain of ii V I sentences
Our own examples
The same numerals played in every key from the root selector, so the claim that a progression is key-independent is something you check rather than accept.
Keep going
Everything in melody and form
- Roman Numeral Analysis
- How to Analyze a Piece