Roman Numeral Notation is a complicated looking approach to writing down the chords of a song. While not necessarily easy to play along with without a good understanding of music theory, much more can be communicated much quicker than with pop chord notation. Additionally, the roman numerals not only tell you the chord but also how the chord functions in the key. The downside is that the notation does not always tell you what notes are or are not present. For your everyday singer, this may seem like overkill or too much information which is why most people use pop chord notation. If you are trying to get very in depth into how music works, song writing, or improvising based on theory knowledge instead of by ear though, roman numeral notation is incredibly useful.
Alright, so first of all we use capital roman numerals to indicate major chords and lowercase roman numerals to indicate minor. So "I" is a major chord and "i" is a minor chord. Next, the chord played is based on the key. In the key of C major "I" is a C major chord but in the key of D major "I" is a D major chord. In the example above, everything is in the key of C. The very first chord is a "V" chord. In the key of C a C is a "I" chord, then "ii" is a d minor, then "iii" is a e minor, "IV" is an F major, therefore the "V" chord is a G major chord.
Next, similar to pop chord notation, putting a number after the numeral means to add a note at that interval to the bass note of the chord. So the "V9"is a G major chord with an added A. You can see the same kind of thing happen in #2 where the "V" chord has a 7 added as well as a flat 9. Now, if you don't have a basis in theory knowledge it will get confusing here. Certain added notes have no impact on the function of a chord. For example, an added 4 to a major chord is basically still the major chord. Many pop songs replace major chords with "sus" chords and the aftermath is more or less the same with a little extra dissonance. Since roman numeral notation tells function while describing the chord, it doesn't care about the sus vs a normal chord.
The more numbers you see, the more strangely built the chord is. An example of this is in #5 above. The "I6" chord is a C chord with an E in the bass. This won't make sense right away, but the short version is that the root of the chord (C) is a 6th from the bass note, but its still a C chord. Looking at a C chord without C at the bottom is often hard to identify as a C chord for beginners. When you see #8 with its V42 b3, its just saying that its a G chord built with a 4th, 2nd, and flat 3rd above the bass. In this case that's F with, G, B, and Ab above it. The same chord in pop notation would be G b2(no5)/F.
Roman numeral notation can get very complicated, so I'll just add a few more small things. First, the octave of a note doesn't matter. In #8 the flat 3 is actually a flat 10, but for simplicity we say flat 3 as octave doesn't matter. Next for diminished chords you use a "o" and for augmented you use "+." See #14 and #15 for diminished chords. "ø" mean half diminished which is similar, so don't be confused by the line through. Since most things in roman numeral notation are about function, anything beyond this will get too advanced for a beginner level theory post such as this. If you'd like additional theory help, please sign up for lessons by clicking here. I've taught theory to college music majors, so I'd be glad to help you!
Comments