Root Progressions

The chords to a given composition are often expressed in term of a Root Progression. (i.e. The Roman Numerals.) At first terms such as 'Imaj9' or 'vim7' will seem complex. As you will see they really aren't and expressing songs in terms of Root Progression is extremely valuable for analyzing, communicating and transposing progressions. Let's start with the 'I Chord.'

The 'I Chord'

We've already determined the notes of the first chord in the Key of C contain the 1st, 3rd and 5th notes (or I, iii and V in Roman Numerals) in the C Major Scale; thus the notes of this chord are C, E and G. This chord is called a C Major (though it's often referred to just as a 'C' as one takes the 'Major' for granted). As it's built from the first note of the scale this chord is also referred to as the 'I Chord' (pronounced "One Chord" as it's a numeral not a letter). Because 'I Chords' are so fundamental to the sound of any given key, musicians have given it yet another special name: the tonic! You'll learn more about its sound and uses later in this document.

The Chord Wheel set for the 'Key of C.' Notice that the 1st, 3rd and 5th (i.e. I, iii and V) notes in the scale are C, E and G. Thus the 'I Chord' is a C (Major) and consists of the notes: C, E and G. It is also called the Tonic.

The 'ii Chord'

Using our pattern of adding every other note from a note in a scale to form chords, starting with the second note in a scale gives us a 'Two Chord.' From our pattern we know that it will contain the 2nd, 4th and 6th notes of the Major Scale in a given key. Collecting the notes from the 'ii, IV and vi' designations (the numerals for 2, 4 and 6) on the Chord Wheel it can be determined that the notes of a basic 'ii Chord' in the 'Key of C' are D, F and A.

Next let's look at the differences between Majors and minors.