Chords are traditionally identified in Lead Sheets with abbreviations of their proper name (C for C major, Cm for C minor, F for F major, Bdim for B dimished, etc.). However, a more useful way to think about chords is in their family relationships.
- All Major Scales consist of a collection of seven notes (out of twelve possible notes used in western music).
- Each note in a scale stands as the root of a chord.
- Using Roman Numerals each of these chords is labeled, respectively: I, ii, iii, IV, V, vi, vii° (where upper case numerals indicate a major chord, lower case a minor and the ° symbol a diminished chord).
- Using Nashville Numbers (less common) each chord is labeled, respectively: 1, 2m, 3m, 4, 5, 6m, 7dim.
- By reducing the chords in a song to a series of numbers, it becomes possible to see the family relationships of one chord to another, and easily transpose the song into any of the twelve possible keys.
- For example: Say you learn a song in the key of C and there are three chords in the song: C, F & G. When you sing this song, it feels too low for your voice and you would prefer to sing it higher. You know that C, F & G are 1, 4 & 5 (using Nashville Numbers) and decide to transpose to the Key of D, so that 1, 4 & 5 are now D, G & A. Now the song feels much more comfortable for your voice.
While some of the twelve major keys are commonly used, others are rare. As a general rule, the farther you get away from the Key of C going around the Circle of Fifths, the less a key is used. C would be the most common, F & G the next, followed by Bb & D, then Eb & A and so on. In learning chord families methodically, it makes sense to start with the most common scales and work toward the less common ones.
TWO IMPORTANT chord substitutions
- Since the major V chord in each key is, at times, interchangeable with the V7 chord (also known as the Dominant Seventh Chord), you’ll be learning both of these chords starting in level 3.
- A true vii° chord is very rare on the ukulele; a V7 usually substitutes for it.