Chord progressions

[bturrell]

I am just beginning to learn music theory, including notation. I've seen a few threads making reference to chord progressions with a notation I'm not familiar with (ii-V-I for example). I was wondering if anyone could explain what this means. I appreciate any help.

Ben

[BigDaddyLoveHandles]

Take the key of C, for example. The notes of the C major scale are numbered:

C - I
D - II
E - III
F - IV
G - V
A - VI
B - VII

Now think of the triads you could build on each note. It will be
a major triad, a minor triad or a diminished triad:

C E G - major
D F A - minor
E G B - minor
F A C = major
G B D - major
A C E - minor
B D F - diminished.

When writing a number for a chord, we often use lower case for minor and upper case for major. So ii-V-I in C means the chords:

D F A
G B D
C E G

Finally, in jazz, seventh chords and higher extensions are part of the furniture. So reading between the lines, that could imply the chords:

D F A C
G B D F
C E G B

[derek]

Explainations don't get any better than that

[bturrell]

Wow, thank you for that. Just one more question, you said upper case for major and lower case for minor. Is there a notation for augmented or diminished?

[derek]

Augmented is upper case, as it is found in dominant chords. Diminished chords are typically seen as passing chords, or function as dominant b9 chords, so again upper case. You will often see a small O used to denote diminished.