Understanding Jazz Theory (Part 1): 3 Most Important Jazz Theory Concepts For A Beginner

1.  4 Chords Families

While these are not the only chord families, these 4 are the main families that make up the diatonic series:

1. Major 7th
   • Symbols: M7, Ma7, Maj7, Δ7
2. Dominant 7th
   • Symbols: 7, dom7
3. Minor 7th
   • Symbols: m7, mi7, min7, -7
4. Minor 7 Flat 5 or Half-Diminished 
   • Symbols: m7(b5), min7(b5), ø7

Next, it is important to understand their chord formulas based off the major scale:

1. Maj7 = 1, 3, 5, 7
2. dom7 = 1, 3, 5, b7
3. min7 = 1, b3, 5, b7
4. min7(b5) = 1, b3, b5, b7

Below is an example of how to construct the 4 major chord types based off C:

Diatonic Harmony

Knowing diatonic harmony, or major scale harmony, is paramount to being able to understand chords in a key and why all these chords are not simply “random.” Songwriters might also find this lesson particularly useful in being able to pick chords from the diatonic series to compose a chord progression.

Here is an example of the diatonic series in the key of C:

This sequence of chords will be true of any key:

• IMaj7, iimin7, iiimin7, IVMaj7, V7, vimin7, viimin7(b5).

For example, in the key of F (F, G, A, Bb, C, D, E):

• FMaj7, Gmin7, Amin7, Bbmin7, C7, Dmin7, Emin7(b5).

Another ex, in the key of D (D, E, F#, G, A, B, C#):

• Dmaj7, Emin7, F#min7, Gmaj7, A7, Bmin7, C#min7(b5).

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3) Church Modes

Using the diatonic sequence of chords, you can derive the church modes, which are the applicable scales for each chord:

• Ioanian, Dorian, Phrygian, Lydian, Mixolydian, Aeolian, Locrian

Here are the modes in C, in diatonic order:

** An easy mnemonic device to remember the diatonic order of the modes is:

• “I Don’t Play Lousy Music Any Longer”.
• I (Ionian) Don’t (Dorian) Play (Phrygian) Lousy (Lydian) Music (Mixolydian) Any (Aeolian) Longer (Locrian).

Let’s take a 2-5-1 in C Major: Dmin7 – G7 – Cmaj7.

A FAQ from beginning improvisers is “do I have to change scales for each chord?” The short answer is no – because the chords are all diatonic to C, you can use the C Major scale to improvise through all 3 chords.

But, in fact, yes – using our church modes, the applicable scales for each chord in that 2-5-1 would be D Dorian, G Mixolydian, and C Ionian. However it is important to keep in mind that this is simply a theoretical technicality – D Dorian, G Mixolydian, and C Ionian are all derivatives of the C Major Scale anyway, just starting on different notes, so whether or not to “change modes” for each chord is only a matter of nomenclature.

Understanding the 4 Chord Families, Diatonic Harmony, and the Church Modes I believe are 3 essential concepts in beginning to connect the dots and wrap your head around jazz theory. In Part 2 of this “Making Sense of Jazz Theory” series we will look at the importance of understanding Functioning Dominants and how that can lead to more advanced theoretical concepts or substitutions – such as: Altered Harmony, Tritone Substitution, Diminished as a 7b9, or Secondary Dominants.

Bijan Taghavi is a pianist, composer, and educator currently based in New York, NY. For more information visit: BijanJazz.com.

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