Number of Chords? Just Starting to Learn Piano
by Don ONeill
(Gold Canyon, AZ, USA)
How many chords are there for each key on the circle of fifth? I looked at chord charts for chord progressions and sometimes it seems like some are missing or are different. Take A Major for example. The chord progression goes:
I: A - C# - E
IV: A - D - F#
V7: G# - D - E
When Looking at chord charts the IV & V7 do not show up. (Learning from a friend that can’t explain it.)
Thank you for your question! From what I can understand, some of the concepts you've learned may have become somewhat "tangled". I will do my best to "untangle" it for you. But it's not a short answer as you might have guessed!
Just to clarify:
1. The chords in your example are:
I: A major chord (in root position),
IV: D major chord (in 2nd inversion) and
V7: E major 7th chord (in 1st inversion omitting the 5th).
2. Chords can be played in different inversions (notes in a different order) and will then look different.
3. Basic chords (triads) can also have notes added to them, like a 7th, 9th etc. Often then another note from the basic chord will be omitted (usually the 5th as in V7 above).
Using the Circle of Fifths:
The circle of fifths is a tool that can be used for different things, one is to easily see the relationships between the main chords in each key.
The main chords in any major (or minor) key are the I, IV and V chords. For example; pick a tonic key (I), lets say A major, on the circle of Fifths. To the right you'll find its dominant (V): E, and to the left you'll find its subdominant (IV): D.
Sometimes in a circle of fifths we also write the minor relative keys inside the circle. Then you will also see that next to A you have F#m (the relative minor key), next to E is C#m, and next to D is Bm.
So, using the circle of fifths, in a major key you'll find 3 chords that are in major, but also 3 chords (relative) in minor. This gives you 6 chords. These are the most important.
Using a Scale to Find Chords:
You can also look at a scale instead of the circle of fifths: Triads can be built from each step (note) in the scale (using only the notes from the scale).
Take the A major scale. Build a triad on each step and you'll get: On step I is A, II is Bm, III is C#m, IV is D, V is E, VI is F#m and VII is G#m (Diminished).
You already know the I, IV and V main chords.
The relative (minor) chords are found on the 2nd, 3rd and 6th step: II, III and VI. There is only one triad left; on the 7th step. This is a diminished chord, (usually used as a dominant 7th chord without the root.)
So, each major or minor scale has 7 chords to use. One from each step in the scale, using only the notes from the scale.
About Chord Progressions:
A chord progression is simply a number of chords put together in a specific order. There are numerous variations of chord progressions!
A chord progression does not have to use only the chords found from one scale. It can be any combination of chords that fit the style of the music.
About Chord Charts:
Finally, chord charts (as chord progressions), however helpful, are limited in that they only show some selected chords, not everything that is possible!
You can read more here for more in depth explanation:
Diatonic Harmony (chords in the scale)
The Circle of Fifths
Common Chord Progressions
The Basics of Music Chords
The Why and How of Roman Numerals in Music
A popular Piano Chord Chart you can print for free
What is Tonic, Subdominant and Dominant etc.