Stop 3 of 6
Triads: how a chord is built
Major, minor, diminished and augmented, and their inversions.
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Stop 3 of 6
Major, minor, diminished and augmented, and their inversions.
You have been playing and barre chords for a while, but what is inside each one? At this stop you open the box: you will see that every basic chord is a stack of two thirds, that there are only four types, and that you can play them anywhere on the neck with three fingers. It is the key to understanding every chord that comes later.
Listen to these three notes one after another, then together:
At first they are a melody; together they become something new: a C chord. That three-note chord is called a , and it is built in a very specific way: by stacking thirds.
In the scale, that means taking every other note: C (D) E (F) G. That is why the notes of a triad are named by their interval from the root: 1, 3 and 5 (root, third and fifth).
| Triad | Floors (bottom + top) | Formula | From C | Symbol | Character |
|---|---|---|---|---|---|
| M3 + m3 | 1 – 3 – 5 | C E G | C | bright, stable | |
| m3 + M3 | 1 – ♭3 – 5 | C E♭ G | Cm | dark, stable | |
| m3 + m3 | 1 – ♭3 – ♭5 | C E♭ G♭ | Cdim | tense, tight | |
| M3 + M3 | 1 – 3 – ♯5 | C E G♯ | Caug | floating, unresolved |
Hear all four in a row on the staff. The root C stays put; only the third and fifth change:
Look at the fifths: major and minor both have a (7 half steps), which is what makes them stable. In the diminished triad the fifth is (6 half steps, a tritone) and in the augmented one it is (8 half steps). That is why those two sound unstable.
A six-string open chord repeats notes: C (x32010) has C, E, G, C, E. But its essence is just three notes, and on guitar you can play them on three neighbouring strings. These small shapes are light, move fast and sound very clear in a band.
Start on strings 3, 2 and 1. Here is C major in three places on the neck, with the degrees marked:
String 3, Fret 5: C4 · 1 · Root
For the minor triad, just lower the third by one fret. Compare the first major shape with the minor one:
String 3, Fret 5: C4 · 1 · Root
On strings 4, 3 and 2 the shapes change a little (the 3–2 shift again), but the idea is the same:
String 4, Fret 2: E3 · 3 · Third
Try it with a barre chord. The E-shape F has six notes but only three different names: F, A and C. See which degree falls on each string:
String 6, Fret 1: F2 · 1 · Root
The root appears three times and the fifth twice, but the third only once, on string 3. That single note decides whether the chord is major or minor: that is why turning F into Fm only takes lifting one finger. And if you play just strings 3-2-1 of that barre (A, C, F), you have a first-inversion triad; on strings 4-3-2 (F, A, C), a root-position one.
The three C shapes you just played contain the same notes in a different order. What matters most is which note is at the bottom, in the bass:
Inversions are written with a slash: C/E means “C chord with E in the bass”. The note after the slash is the bass, not a new chord.
The main reason to use inversions is to create smooth bass lines. Listen to this progression: the bass steps down note by note (C, B, A, G) thanks to one inversion:
Play G on string 1, fret 3, and let it ring. Which chord would you put under it? There is more than one answer, because the same note can take any of the three jobs in a triad:
On strings 3-2-1 all three chords sit in the same area, and the top note stays put:
Listen to the result. The top never changes, yet each chord paints it a different colour: bright under C, wistful under Em, settled under G.
Watch your hand too: from C to Em only one note moves, down a half step (C → B). From Em to G, another one drops a whole step (E → D). The more notes two chords share, the smoother the change sounds and the less your fingers travel.
Change the quality as well and you get three more options: G is the root of Gm, the third of E♭ and the fifth of Cm. For Cm, for example, just drop string 2 to fret 4. Six different chords for a single note.
These two triads are less common, but they bring colour and motion.
The diminished triad appears naturally in the major scale: in C major, the triad on B is B–D–F. Between B and F there is a , and that makes it ask for movement. You will meet it again at the next stop.
String 3, Fret 4: B3 · 1 · Root
The augmented triad is symmetrical: both its thirds are major, so it splits the octave into three equal parts (4 + 4 + 4 half steps). Move the shape four frets and you get the same three notes in a different order.
String 3, Fret 5: C4 · 1 · Root
Play each shape twice as half notes, then change. As you play, say which degree is in the bass: “one”, “three”, “five”.
Once it flows, do the same with Cm: lower the third by one fret in every shape.
Goal: Move up and down through the three C major shapes on strings 3-2-1 with no gaps between shapes, at 80 BPM.
With triads on strings 3-2-1, C, Am, F and G all fit in the same area of the neck. Notice how many notes carry over from one chord to the next: your fingers barely move.
Goal: Play the whole progression with triad shapes, without gaps between chords, over the backing at 80 BPM.
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