Module 2: Theory ILesson 2beginner⏱ 75 min + two weeks of drills

The major scale, keys and the circle of fifths

Build the major scale from its formula, learn the key signature of every key, understand the circle of fifths and relative minor, and spell scales with the right accidentals.

Why the major scale is the measuring stick

Almost everything in jazz harmony is described relative to the major scale. Chord formulas (1 3 5 b7), scale formulas (1 2 b3 4 5 6 7), tensions (9, #11, 13): all of these numbers are degrees of the major scale, raised or lowered. If you know the major scale in every key, you have the ruler against which every other sound is measured. You also need keys: a tune "in Eb" means its chords are built from the Eb major scale, and a horn player calling "Bb blues" expects you to know what notes that implies without a chart.

This lesson builds on the first scale lesson, where you played the major scale in position. Here you learn why it has the notes it has, how the twelve keys relate, and how to spell a scale so that other musicians can read it.

Building the scale: whole steps and half steps

The major scale is seven notes arranged in the pattern W W H W W W H (whole, whole, half, whole, whole, whole, half), which brings you back to the starting note an octave higher. On one string that is 2 frets, 2 frets, 1 fret, 2, 2, 2, 1. Play it from C at the 3rd fret of the 5th string and look at the fret numbers: the two half steps fall between the 3rd and 4th degrees and between the 7th and 8th.

\tempo 80
.
\ts 4 4
:4 3.5{txt "1"} 5.5{txt "2"} 7.5{txt "3"} 8.5{txt "4"} | 10.5{txt "5"} 12.5{txt "6"} 14.5{txt "7"} 15.5{txt "8"} |

In interval terms (see the intervals lesson) the degrees of the major scale above the root are: major 2nd, major 3rd, perfect 4th, perfect 5th, major 6th and major 7th. Every degree is major or perfect; that is exactly what "major" means in a chord or interval name, and why we write the major scale as plain 1 2 3 4 5 6 7.

The position fingering, with one key in mind

Here is the two-octave fingering with the root on the 6th string, in G major. The 7th degree is F#, not F: the formula demands a whole step from E and a half step up to G. Play it up and down with alternate picking and say the note names, not the fret numbers.

\tempo 84
.
\ts 4 4
:8 3.6 5.6 2.5 3.5 5.5 2.4 4.4 5.4 | 2.3 4.3 5.3 3.2 5.2 2.1 3.1 r | 3.1 2.1 5.2 3.2 5.3 4.3 2.3 5.4 | 4.4 2.4 5.5 3.5 2.5 5.6 3.6.4 |

Move the whole shape down two frets, so the root sits at the 1st fret, and you are playing F major. One note changes name: the 4th degree is now Bb. You will shortly see why F major has a flat while G major has a sharp.

\tempo 84
.
\ts 4 4
:8 1.6 3.6 0.5 1.5 3.5 0.4 2.4 3.4 | 0.3 2.3 3.3 1.2 3.2 0.1 1.1 r |

Spelling rules: why G major has F#, not Gb

A major scale uses each letter name exactly once, in alphabetical order. G major runs G A B C D E and then needs a note a half step below G. The letter must be F, so the note is F#. Writing Gb would give you two Gs and no F, and a reader would see a scale with a repeated letter and a gap, which is confusing in a chart and wrong on an exam.

The same rule decides flats. F major runs F G A and then needs a note a half step above A. The letter must be B, so it is Bb, not A#. Once you adopt the rule, every major scale spells itself: start on the root, write the next six letters, then add whatever sharps or flats the W W H W W W H pattern requires. The scale finder will show you any scale spelled correctly if you want to check your work.

Key signatures

A key signature is the list of sharps or flats a key needs, written once at the start of the staff so they do not have to be repeated on every note. Because of the spelling rule, each major key has a fixed number of sharps or flats, and they always arrive in the same order.

Two patterns to memorise from the table:

• Sharps are added in the order F C G D A E B. Each new sharp key has one more sharp than the last, and the newest sharp is always the 7th degree of the new key (the "leading tone"). So a key signature with three sharps (F C G) is the key one half step above the last sharp: A major.
• Flats are added in the order B E A D G C F, the sharp order backwards. The newest flat is the 4th degree of the key, and the key is named by the second-to-last flat: with four flats (B E A D), the key is Ab major. (F major, with one flat, is the exception you simply remember.)

Keys with six or seven accidentals have enharmonic twins: F# major and Gb major contain the same pitches with different spellings, and the same goes for B and Cb, and for C# and Db. Jazz charts use the flat spellings for these in almost every case, because flat keys are friendlier for horns.

The circle of fifths

Arrange the keys so that each one is a perfect 5th above the last and you get the circle of fifths: C, G, D, A, E, B, F#/Gb, Db, Ab, Eb, Bb, F and back to C. Going clockwise each key gains a sharp; going anticlockwise (which is the same as moving up in 4ths) each key gains a flat. Keys next to each other on the circle share six of their seven notes, which is why modulations between neighbours sound smooth.

Jazz musicians use the anticlockwise direction constantly, because chord roots in jazz progressions move in 4ths far more often than any other way (ii to V to I is two moves up a 4th). Practising anything "around the cycle" means playing it in C, then F, then Bb, Eb, Ab, Db, Gb, B, E, A, D, G. Learn the order now; it is the standard way to run a drill through all twelve keys.

\tempo 80
.
\ts 4 4
:4 8.6{txt "C"} 8.5{txt "F"} 6.6{txt "Bb"} 6.5{txt "Eb"} | 4.6{txt "Ab"} 4.5{txt "Db"} 2.6{txt "Gb"} 2.5{txt "B"} | 0.6{txt "E"} 0.5{txt "A"} 10.6{txt "D"} 10.5{txt "G"} | 8.6.1{txt "C"} |

The fretboard makes the circle visible: a 4th up is the next string at the same fret, so every pair of roots at one fret on strings 6 and 5 is a step around the cycle, and the whole cycle is a staircase of pairs descending two frets at a time.

Relative minor

Every major key has a relative minor that shares its key signature and all of its notes. The relative minor starts on the 6th degree of the major scale, a minor 3rd (three frets) below the major root. C major and A minor share the same seven white notes; Eb major and C minor share three flats. The second column of the key-signature table lists the relative minor for each key.

The two scales have identical notes but a different home. Play them back to back and the difference is obvious: the first bar sounds bright and settled on C, the second sounds darker and settles on A.

\tempo 84
.
\ts 4 4
:8 3.5 0.4 2.4 3.4 0.3 2.3 0.2 1.2 | 0.5 2.5 3.5 0.4 2.4 3.4 0.3 2.3 |

Relative keys matter in jazz because so many standards move between a major key and its relative minor within a single chorus. The minor scales lesson takes up what happens to the minor scale next.

Seeing a key on the whole neck

Once you know the key signature, every note of the key can be found anywhere on the fretboard. The map below shows G major from the open strings to the 12th fret, labelled by degree. Find the three F#s and notice that nothing else is sharp.

Compare with Eb major, three flats: the shapes are identical, moved to different frets, but the note names are completely different. That is the point of this lesson: the shapes are the easy part, and knowing the names is what lets you talk to other musicians.

Exercises

1. Spell aloud. Pick a key from the circle. Say its seven notes in order from the root, then say its key signature. Check with the table. Do all twelve keys in cycle order (C F Bb Eb ...), then in fifths order (C G D A ...).
2. One string, every key. Play the W W H W W W H pattern on the 5th string from each of the twelve roots, naming the notes.
3. Position fingering around the cycle. Play the two-octave 6th-string-root fingering in C (root at fret 8), then F (fret 1 or 13), Bb (fret 6), Eb (fret 11), Ab (fret 4), Db (fret 9), Gb (fret 2), B (fret 7), E (fret 12 or open), A (fret 5), D (fret 10), G (fret 3). Say the name of the root before you start each one.
4. Signature to key. Have someone (or the reference page) show you a number of sharps or flats; name the major key and its relative minor as fast as you can.

Quiz