Jazz Theory

Chord Construction – Part 1
Triads and 7th Chords

On this page you’ll find jazz theory about chord construction, first with simple triads (three-note chords) then with “more complicated” (should I say jazzier?!) chords that have 4 notes and more…

If you don’t read music (“notes” on the staff) and if you’ve never encountered any music theory in the past, this is a good place to start. Go slow, read on and don’t be afraid to ask questions!

In the course of this jazz theory article series about chord construction, you’ll find music theory info about triads and sevenths chords, how to add extensions, chord equivalents, diatonic chords and finally a neat theoretical process to understand what extensions are “allowed” on jazz chords.

My goal here is to have you realize that you already know thousands of chords. (that is, if you already play a little bit) Why? Well, since any single chord can be put to use in many different contexts, it’s not a matter of learning more chords… it’s only a matter of finding more USES to the ones you already know! (-:

Jump to a page:

Chord Construction 1: Triads and Sevenths [You’re Here]
Chord Construction 2: Adding Extensions
Chord Construction 3: Equivalents
Chord Construction 4: Chords from three scales

Addendum: The “Chord Extensions Finder” Technique



  • “Chord” means that all the notes are sounded together, at the same time.
  • The major scale serves as reference when identifying chords by scale degrees… and that’s exactly what numbers mean on this page.For instance, 1 3 5 means to play the first, third and fifth notes of the major scale. It goes for any chord found on this page. Degrees are raised by a sharp symbol (#) and lowered by the flat symbol (b).
  • Chords are built in intervals of ascending THIRDS (2 or more)This works 99% of the time. A third is the space (called “interval”) between two non-consecutive scale notes, up or down. For instance C-E is an ascending third (say “C D E” in your mind). Same thing works descending: C-A is a third (say “C B A” in your mind) but with chords, we won’t deal with descending intervals.
  • So, a chord will usually contain ODD numbers like this 1 3 5 7 9 11 13, up to a maximum of 7 notes (on this website at least)



Triads are built of three notes. This is like the prequel to jazz theory. Their exists four main types of triads: major, minor, augmented and diminished. The reason behind this is simple: triads are three notes stacked up and between each note lies the interval of a third.

Triads construction:
1st NOTE -[space]- 2nd NOTE -[space]- 3rd NOTE

The [space] is the interval of a third. This interval can be qualified to be either major or minor.

Since there only exists two “types” of third interval, we are left with only four possible combinations of triads.

  • MAJOR TRIAD: 1 3 5
    Intervals : maj3rd then min3rd (as in C-E-G)
  • MINOR TRIAD: 1 b3 5
    Intervals : min3rd then maj3rd (as in C-Eb-G)
    Intervals : min3rd and min3rd (as in C-Eb-Gb)
    Intervals : maj3rd and maj3rd (as in C-E-G#)

Other types of triads also exist such as SUS4: 1 4 5 and SUS2: 1 2 5. You can expect to see those two quite a lot in popular songs. The “SUS” means suspended, and in fact the note replacing the “3” in both cases is said to be a suspension of that “3”.

The two oddballs that I personally wish to leave with no names for now are 1 3 b5 and 1 b3 #5 … these are not common at all.

For applications on the fretboard, see this “Triads by String Sets” video:

… and now for the real jazz theory.


Seventh Chords

We apply the same process as above, but this time we have four notes stacked and thus THREE third intervals. Once more, that “space” (the third) can be qualified major or minor, hence creating all the variety found in 7th chords.

We have WAY more combinations available than we had with the triads, so hang on to your hats! Here are the four main seventh chords used in jazz theory (they constitute 90% of what’s on sheet music):

  • MAJOR SEVENTH: 1 3 5 7
    Intervals within : (all thirds) maj, min, maj
    As in C-E-G-B
  • MINOR SEVENTH: 1 b3 5 b7
    Intervals within : (all thirds) min, maj, min
    As in C-Eb-G-Bb
  • DOMINANT SEVENTH: 1 3 5 b7
    Intervals within : (all thirds) maj, min, min
    As in C-E-G-Bb
  • MINOR SEVENTH FLAT 5TH: 1 b3 b5 b7
    Intervals within : (all thirds) min, min, maj
    As in C-Eb-Gb-Bb — (aka “Half-diminished”)

In jazz theory, the “chord types” above are considered the main 7th chords. They all “live” in the major scale. You’ll find them by stacking thirds on each note of the major scale … in fact, it’s a good idea for guitarists to learn chords in scales like this, as explained here.


Of course, because of the amount of possible combinations, here a more seventh chords:

  • MINOR w/ MAJOR SEVENTH: 1 b3 5 7
    Intervals within : (all thirds) min, maj, maj
    As in C-Eb-G-B
  • DIMINISHED SEVENTH: 1 b3 b5 bb7
    Sometimes spelled 1 b3 b5 6
    Intervals within : all minor thirds.
    As in C-Eb-Gb-Bbb (or C-Eb-Gb-A)
  • MAJOR SIXTH: 1 3 5 6
    As in C-E-G-A
  • MINOR SIXTH: 1 b3 5 6
    As in C-bE-G-A
  • MAJOR SEVENTH #5: 1 3 #5 7
    Intervals within : (all thirds) maj, maj, min
    As in C-E-G#-B

This next one is more appropriately named “maj7th #11” most of the time. It reflects the lydian mode, and therefore, it’s a RAISED 4th (and not a LOWERED 5th) … In any case, it’s fine as long as you know “what’s what”.

  • MAJOR SEVENTH b5: 1 3 b5 7
    Usually called maj7(#11)
    As in C-E-F#-B

Those two next are discussed on other pages of JazzGuitarLessons.net … there’s some need for jazz theory explanation because of that relationship of b5=#4 and of #5=b6. It all makes sense when you know the harmonies found within the scales…

  • DOMINANT SEVENTH b5: 1 3 b5 b7
    Intervals within : (all thirds) maj, min, min
    As in C-E-G-Bb
    Follow this link for more info on Dom7(b5) (in fact Dom7(#11)
  • DOMINANT SEVENTH #5: 1 3 #5 b7
    As in C-E-G#-Bb
    Follow this link for more info on Dom7(#5) (in fact Dom7(b13))

Wanna Play Those on the Guitar?
See the Chord Charts in the “Chords” section of JazzGuitarLessons.net for a complete reference

That’s all for the (most common) 7th chords. But wait! Aren’t we seeing a lot of “9” and “13” in jazz theory? You betcha!


And the rest…

What about chords with 13, 11 or 9 (or all of them!) ? Just add 9-11-13 on top! … right?! So the short answer is : ALMOST but not quite! That’s what we’ll tackle in the second installment of this Jazz Theory series…

Jump to a page:

Chord Construction 1: Triads and Sevenths [You’re Here]
Chord Construction 2: Adding Extensions
Chord Construction 3: Equivalents
Chord Construction 4: Chords from three scales

Addendum: The “Chord Extensions Finder” Technique

2 thoughts on “Jazz Theory

    • Unfortunately not, Chris. If I expand upon some more triadic materials for the website, I am (for sure!) going to include some of these ideas and notate them in a PDF. It’s all about “spread” triads, so fun to play with.

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