The Key of One Part 3: Chord Theory


Continuing our adventure of learning musical concepts without traditional notation, we’re going to look at chords this month. I’ll be talking about the note numbering system established in previous “The Key of One” columns (from the January and February 2015 issues), so those will be helpful to have on hand, and should be in the “Keyboard 101” section of our website by the time you read this.

Nearly every song you hear or play uses chords, which, at their most basic, are groups of three notes (triads) with a 1 (the root note) and a 5 on either side, and either a major or minor third in the middle. These fundamental building blocks have many relationships based on the keys and scales in which they are used, and if you know your way around that chord matrix, you can better acquaint yourself with the variety of choices you can make as a songwriter and performer. Be sure to check the slide show below for various chord diagrams!

Triad Treatments

There are three things you can do with triads:

1. Move around in the middle by choosing between major and minor thirds, or suspending use of the third in favor of the 2 (sus2) or the 4 (sus4).

2. Raise (augment) or lower (diminish) the fifth by one half-step. That’s the closest key on your keyboard to the “regular” fifth, whether it’s black or white.

3. Build more notes on top of the chord with sixths, sevenths and the ninth, eleventh, and thirteenth. In fact, these last three can be thought of as the repurposed 2, 4, and 6 added on top.

I use the analogy of the basic triads being the “cake” and all the extensions and tweaks being the “frosting.” When you’re in tune with your basic triads, you can always see the cake through the frosting. I deal with a lot of students who get lost in the frosting, and I realize that if they don’t have a grasp of their triads, they don’t have any comprehension of the structural movements in the arrangement. I always recommend they dig back into basic triads to solidify their foundation so that any addition or tweak doesn’t take their ear away from the triads their understanding. And remember: 12 keys with a major and minor triad in each makes a grand total of 24 basic triads to with which to become familiar. When you look at it that way, 24 doesn’t seem like such an overwhelming number of chords to get acquainted with, does it?

Here are some further ways to build your knowledge of chord theory while also giving yourself a great foundation for soloing and improvising.

Practice Your Inversions

To become more familiar with chords, practicing inversions is one of the best things you can do. What’s an inversion? You can actually play the same basic triad chord with the notes in three different orders. There’s the root position, which has notes 1, 3, and 5 in ascending order. The first inversion goes 3, 5, and 1 in ascending order (i.e., the root note is actually an octave up, on top. The second inversion places the root in the middle, ascending in order of 5, 1, and 3.

Practice with a single hand at a time to focus on what you’re doing. Start with C major and play through the inversions up and down two or three octaves. First do it harmonically, then arpeggiate the inversions and play them melodically.

Once you are comfortable, add the note one octave up from whatever the lowest note is in the inversion you’re playing. This will have you playing two positions at the same time, which will supercharge this exercise. So, your first position encompasses the root and the first inversion (1 is the octave), your second position encompasses the first and second inversion (3 is the octave), and your last position is second and root inversion (5 is the octave). Do this for each of the 24 chords, and as you get familiar, they’ll fall easily under your commanding fingers. Because all songs are ultimately based on these kinds of chord structures, this is one of the most crucial exercises to practice.

Find the Similarities

As noted, there are 24 chords, but many of them share similar shapes—by which I mean how they look and feel on the piano keyboard with regard to (a) distance between keys and (b) proportion of white and black keys used.

How many shapes? Well, if you factor in that Eb minorand Gb could be the same shape because they’re all on the black keys, then only then basic types of chord shapes exist. Knowing this, you can focus on practicing one shape at a time using different chords. Here’s the breakdown of the ten positions, grouped by similarity.

1. C, Dmin, Emin, F, G, Am.

2. Cmin, Fmin, Gmin.

3. A, D, E.

4. Ab, Db, Eb.

5. Gbmin, Abmin, Dbmin.

6. Ebmin, Gb.

7. Bb.

8. Bbmin.

9. B.

10. Bmin.

Those last four chords are unique, so each is in a group by itself. Play through your inversions using these groupings and you will notice with the first six, the shapes of the chords and their inversions are exactly the same. This is how we focus on commonalities to reduce the “size” of music for a more manageable learning experience.

We build on these common shapes to help us become familiar with chords and how and where we choose to play them. When you do this, your hands will begin to find the closest inversions intuitively as you run through chord changes. In fact, with all of the overlap of chords and inversions on the piano, you could play every single one of those 24 chords without moving your hand off of the middle position. Try that as an added exercise; you’ll boost your ability to navigate the chord matrix and make every song easier to play.

In the next “The Key of One” column, we’ll learn tricks and tips for better improvising, songwriting, and chord choices. See you next month!

Robbie Gennet is a touring keyboardist, guitarist, longtime Keyboard contributor, and educator at Musicians’ Institute in Hollywood, California. His book, The Key of One (Alfred Music) outlines a thorough method for understanding music without learning traditional notation. You can get it at, and take private lessons from Robbie at

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