Roman Numeral
I, V and their friends — chords labelled by degree inside a key
Related
Roman numerals label a chord by its degree and quality inside a key: uppercase for major, lowercase for minor, ° for diminished and + for augmented triads.
The notation abstracts away letter names, so the same progression looks identical in every key and modulations or sequences are easy to see. Added figures such as 6, 6/4 or 7 mark inversions and seventh chords.
Avoid reading numerals as absolute chord names: a V means nothing without a key, and borrowed chords need flats or sharps, as in ♭VI or ♯iv°. Establish the key first, then read the number.
Sources
- 罗马数字和声标记的级数与性质，参 The New Grove Dictionary of Music and Musicians, "Analysis"；本文为原创表述
Used for fact-checking only; all prose is original.