Module 2: Theory ILesson 3beginner⏱ 90 min + three weeks of drills

Triads

Build major, minor, diminished and augmented triads from stacked 3rds, spell them in every key, and play their close-position shapes with inversions on three string sets.

Why a jazz guitarist needs triads

Triads are the simplest chords, and it is tempting to skip them on the way to the four-note voicings jazz is known for. Do not. Every seventh chord is a triad with one more note; every voicing you will learn later is a triad somewhere inside it; and the most modern-sounding devices in the course, upper-structure triads and triad pairs, are nothing but the shapes in this lesson played over a different bass note. Players who know their triads in all inversions on all string sets can harmonise a melody on the spot, comp without getting in a pianist's way, and hear chord quality instantly. This lesson builds that foundation.

Four qualities from two kinds of 3rd

A triad is three notes built in 3rds: a root, a 3rd above it and a 5th above the root. Since a 3rd can be major (four frets) or minor (three frets), stacking two of them gives four combinations, and those are the four triad qualities.

Read the formula column against the major scale from the previous lesson:

• Major (1 3 5): a major 3rd, then a minor 3rd on top. The 3rd and 5th are exactly as they appear in the major scale. Symbol: just the root (C), sometimes Cmaj or CΔ in charts.
• Minor (1 b3 5): a minor 3rd, then a major 3rd. Lower the 3rd of the major triad by one fret. Symbol: Cm, also written C- or Cmin.
• Diminished (1 b3 b5): two minor 3rds. Lower both the 3rd and the 5th. Symbol: Cdim or C°. The outer interval is a diminished 5th, the tritone from the intervals lesson, which is why the chord sounds unstable.
• Augmented (1 3 #5): two major 3rds. Raise the 5th of the major triad. Symbol: Caug or C+. The outer interval is an augmented 5th, and because the chord divides the octave into three equal parts, it sounds like it has no root at all.

Hear the four qualities from the same root. In this exercise each triad is played as an arpeggio from C on the 5th string; the 3rd and 5th sit on the 4th string.

\tempo 76
.
\ts 4 4
:4 3.5{ch "C"} 2.4 5.4 r | 3.5{ch "Cm"} 1.4 5.4 r | 3.5{ch "Cdim"} 1.4 4.4 r | 3.5{ch "Caug"} 2.4 6.4 r |

Spelling triads in every key

To spell a triad, take the root, skip a letter for the 3rd, skip another for the 5th, then adjust with accidentals to get the right intervals. For a major triad the fastest method is: the 3rd and 5th are the 3rd and 5th degrees of the major scale on that root. For minor, flatten the 3rd. For diminished, flatten the 3rd and the 5th. For augmented, sharpen the 5th.

Because the letter rule always applies, a few triads need double sharps or double flats when spelled strictly. Those are rare in practice: a chart will never ask you to play "Bbdim" with its 5th spelled Fb and you will still play the right fret, but you should know why the spelling exists. The table below shows all twelve major triads; use the chord dictionary to see any other quality on any root.

Close position and inversions

A triad is in close position when its three notes sit within one octave, as tightly as possible. Which note is on the bottom gives the inversion:

• Root position: root on the bottom (1 3 5 from low to high).
• First inversion: 3rd on the bottom (3 5 1).
• Second inversion: 5th on the bottom (5 1 3).

The chord is the same chord in every inversion. The reason to learn all three is practical: on guitar, each inversion is a different shape at a different fret, and whichever one is nearest is the one you grab. The chord diagrams below come straight from the voicing library; each is labelled with its notes.

String set 3-2-1

The top three strings give the brightest triads, the ones you will use for chord melody and for comping above a bass player. The B-string tuning means the shapes are not symmetrical, so learn them by shape and by which note is in the bass.

\tempo 72
.
\ts 4 4
:4 (5.3 5.2 3.1){ch "C"} (9.3 8.2 8.1) (12.3 13.2 12.1) (9.3 8.2 8.1) | :4 (5.3 5.2 3.1) (0.3 1.2 0.1) (5.3 5.2 3.1).2 |

Now the other three qualities on the same strings. Compare each shape with the major triad it came from: the minor shape has one note lowered, the diminished shape two, and the augmented shape one note raised. If you can see those single-fret differences, you never have to memorise the qualities as separate shapes.

\tempo 72
.
\ts 4 4
:4 (5.3 4.2 3.1){ch "Cm"} (8.3 8.2 8.1) (12.3 13.2 11.1) r | :4 (5.3 4.2 2.1){ch "Cdim"} (8.3 7.2 8.1) (11.3 13.2 11.1) r | :4 (5.3 5.2 4.1){ch "Caug"} (9.3 9.2 8.1) (13.3 13.2 12.1) r |

Notice the augmented triad: its three inversions are the same shape moved up four frets each time, because every interval in the chord is a major 3rd. The diminished triad has a similar near-symmetry you will exploit when you meet diminished seventh chords.

String sets 4-3-2 and 5-4-3

The middle strings give a warmer sound that sits well under a horn or voice. Here are the C major shapes on both sets, and an exercise that climbs through the inversions on each.

\tempo 72
.
\ts 4 4
:4 (5.4 5.3 5.2){ch "C"} (10.4 9.3 8.2) (14.4 12.3 13.2) r | :4 (3.5 2.4 0.3) (7.5 5.4 5.3) (10.5 10.4 9.3) r |

Strings 5-4-3 and 4-3-2 are both tuned in 4ths, so the three shapes on 5-4-3 are the same as the three shapes on 6-5-4 and nearly the same as the ones on 4-3-2 (the latter still cross no B string). Once the 3-2-1 set is comfortable, the lower sets are mostly a matter of the same fingerings on different strings.

Triads in a progression: voice leading

Inversions earn their keep when chords change. Instead of jumping to a new root-position shape for every chord, choose the inversion of the next chord that is closest to where your fingers already are. In the example below, a C major triad moves to F, then G, then back to C, and no voice moves more than two frets. The lowest note of each shape is not always the root, and that is fine: a bass player or your own thumb will supply it.

\tempo 80
.
\ts 4 4
:2 (5.3 5.2 3.1){ch "C"} (5.3 6.2 5.1){ch "F"} | (4.3 3.2 3.1){ch "G"} (5.3 5.2 3.1){ch "C"} |

This is the principle of voice leading, and it governs every voicing module later in the course: move each voice to the nearest available chord tone. Practise it now with triads and the four-note chords will fall into place.

Why triads matter later

Three things to look forward to. First, a seventh chord is a triad plus a 7th, so when you reach the next module you already know three-quarters of every chord. Second, jazz players often play only the top part of a chord: over a G7 a pianist might play an A major triad, giving the 9, #11 and 13 of the dominant chord; that is an upper-structure triad, and it is just a major triad shape from this lesson. Third, triads make excellent melodic material: a line built from a triad arpeggio outlines the harmony clearly, and alternating two triads (a triad pair) is one of the most common modern improvising devices. All three uses depend on knowing the shapes here cold.

Exercises

1. Spell before you play. For each quality, pick a root, spell the triad aloud, then play it on strings 3-2-1 in root position. Check with the chord dictionary.
2. Three inversions, one string set. Choose a quality and a root. Play the three inversions up the neck and back down on 3-2-1, then 4-3-2, then 5-4-3, naming the bass note of each shape.
3. One shape, twelve roots. Take one shape (say, C major first inversion on 3-2-1) and move it around the cycle of 4ths (C F Bb Eb ...). Say the root each time; the root is not the lowest note, so you must know which finger is on it.
4. Quality switch. Hold a major shape and, without moving the hand, change it to minor, then diminished, then back to major, then augmented. Do this in all three inversions.
5. Nearest inversion. Play I–IV–V–I in G, F and Bb on strings 3-2-1 using the closest inversion for each chord, as in the voice-leading example.

Quiz