This guide assumes that you can name the notes of the treble staff, count quarter and eighth notes, and find the natural notes in open position. It moves from names to relationships: intervals, keys, chords, cadences, and the markings that shape a performance. The goal is not to memorise more facts. The goal is to look at a page and hear what it is doing.

Intervals are the grammar

An interval is the distance between two pitches. It has a number, counted in letter names, and a quality. From C up to E is a third, because C, D and E are three letter names. It is a major third, because the distance is four semitones. From C up to Eb is also a third, but it is a minor third, three semitones.

The quality matters as much as the number. Major and minor apply to seconds, thirds, sixths and sevenths. Perfect applies to unisons, fourths, fifths and octaves. Augmented and diminished describe an interval that has been widened or narrowed by another semitone.

Semitones  Interval
0          unison
1          minor 2nd
2          major 2nd
3          minor 3rd
4          major 3rd
5          perfect 4th
6          tritone
7          perfect 5th
8          minor 6th
9          major 6th
10         minor 7th
11         major 7th
12         octave

Intervals larger than an octave are compound. A ninth is an octave plus a second, an eleventh is an octave plus a fourth, and a thirteenth is an octave plus a sixth. In chord symbols these compound intervals are common, especially in jazz.

An interval can be inverted by moving the lower note up an octave or the upper note down an octave. A third becomes a sixth, a fourth becomes a fifth, and a second becomes a seventh. The quality also changes: major becomes minor, and perfect stays perfect. Inversion is one reason a chord can be voiced in several places on the guitar and still keep the same function.

Scales, keys and the circle of fifths

A major scale follows the pattern whole, whole, half, whole, whole, whole, half. In C major the notes are C D E F G A B C. The half steps fall between E and F, and between B and C. Those two places are the only semitones in the scale, and they are what give the major scale its bright, stable sound.

Each note of the scale is a degree. The first degree is the tonic, the fifth is the dominant, and the seventh is the leading tone. The leading tone sits one semitone below the tonic and pulls strongly toward it. A melody that ends on the leading tone feels unfinished; a melody that resolves to the tonic feels complete.

A key signature collects the sharps or flats of a key at the start of the staff. The order of sharps is F, C, G, D, A, E, B. The order of flats is the reverse. The last sharp is the leading tone, one semitone below the tonic. The last flat is the fourth degree of the major key, so a single flat, Bb, means F major.

The circle of fifths arranges the keys by that interval. C major has no accidentals. Moving up a fifth adds a sharp: G, D, A, E, B, F#, C#. Moving down a fifth adds a flat: F, Bb, Eb, Ab, Db, Gb, Cb. The circle is a map of key relationships, and it is also a map of chord relationships: the chords next to a key on the circle are the ones most likely to appear in its music.

Every major key has a relative minor three semitones below its tonic. C major and A minor share a key signature. G major and E minor share one. The natural minor scale uses the same notes as its relative major, but it starts on the sixth degree and therefore has a different tonic and a different sound.

C major:        C  D  E  F  G  A  B  C
A natural minor: A  B  C  D  E  F  G  A
A harmonic minor: A  B  C  D  E  F  G# A
A melodic minor:  A  B  C  D  E  F# G# A

The harmonic minor raises the seventh degree, which creates a leading tone and an augmented second between the sixth and seventh degrees. The melodic minor raises the sixth and seventh degrees on the way up and usually returns to the natural minor on the way down in classical practice. Jazz players often use the ascending form in both directions.

Chords and Roman numerals

A triad is three notes stacked in thirds. A major triad uses the root, major third and perfect fifth. A minor triad lowers the third. A diminished triad lowers the third and the fifth. An augmented triad raises the fifth.

Triad       Formula     Example in C
Major       1 3 5       C
Minor       1 b3 5      Dm
Diminished  1 b3 b5     Bdim
Augmented   1 3 #5      C+

A seventh chord adds a fourth note. The common types are the major seventh, the dominant seventh, the minor seventh, the half-diminished seventh and the diminished seventh.

Chord          Formula        Example in C
Major 7        1 3 5 7        Cmaj7
Dominant 7     1 3 5 b7       G7
Minor 7        1 b3 5 b7      Dm7
Half-diminished 1 b3 b5 b7     Bm7b5
Diminished 7   1 b3 b5 bb7    Bdim7

A chord can be inverted by moving the lowest note up an octave. The root position has the root in the bass, the first inversion has the third in the bass, and the second inversion has the fifth in the bass. Figured bass writes these as 53, 6 and 64 for triads, and 7, 65, 43 and 4/2 for seventh chords. On the guitar an inversion is a voicing: the same chord with a different note on the lowest string.

Roman numerals describe the chords of a key. Uppercase means a major or dominant chord, lowercase means a minor chord, and a small circle or the word diminished means a diminished chord. In C major the diatonic chords are:

I      Cmaj7
ii     Dm7
iii    Em7
IV     Fmaj7
V      G7
vi     Am7
vii    Bm7b5

The pattern is the same in every major key: major, minor, minor, major, major, minor, diminished. The pattern for natural minor is minor, diminished, major, minor, minor, major, major. Learn the pattern once and you can find the chords of any key without recalculating them from scratch.

Functional harmony and cadences

Chords have jobs. The tonic is home: I and vi in major, i and III in minor. The predominant prepares the dominant: ii and IV in major. The dominant creates tension and points back to the tonic: V and vii in major. A progression is a path through those jobs.

A cadence is the end of a phrase. An authentic cadence moves from V to I and feels final. A half cadence ends on V and feels open. A plagal cadence moves from IV to I and has a softer, hymn-like sound. A deceptive cadence moves from V to vi and delays the expected resolution.

I - V - vi - IV       a common pop loop
ii - V - I            the basic jazz cadence
I - IV - V            a simple rock and blues loop
i - bVII - bVI - V    the Andalusian cadence in minor

The twelve-bar blues is a form as much as a progression:

I   I   I   I
IV  IV  I   I
V   IV  I   V

Voice leading is the art of moving from one chord to the next with smooth lines. Keep common tones where they are, move the other voices by step when possible, and resolve the leading tone upward to the tonic. Parallel fifths and octaves are avoided in classical style because they make the voices sound less independent. In guitar music the same principles apply to the bass line and to the inner voices of a chord.

Reading the whole score

A score carries more than pitches and rhythms. Tempo markings tell you how fast the music should go: Adagio is slow, Andante is walking pace, Moderato is moderate, Allegro is fast, and Presto is very fast. Ritardando means gradually slower; accelerando means gradually faster.

Dynamic markings tell you how loud to play. p is piano, soft; f is forte, loud; mp and mf are the middle levels. A crescendo grows louder, a diminuendo grows softer, and sfz is a sudden accent. Articulation markings tell you how to start or connect a note: staccato is short and detached, tenuto is held for its full value, an accent emphasises the attack, and a slur connects notes without re-articulating them.

Repeat signs send you back to an earlier bar. First and second endings tell you what to play on the repeat. D.C. al Fine means go back to the beginning and play to the word Fine. D.S. al Coda means go back to the sign and then jump to the coda when directed. These marks are navigation, not decoration: read them before you start, or you will learn the piece in the wrong order.

An anacrusis, or pickup, is a note or two before the first full bar. Count it as part of the phrase but not as the first beat of the bar. Guitarists also meet the bass clef and the alto clef when reading piano scores or ensemble parts. The treble clef remains the main clef for guitar, but the ability to read the others opens a lot of music.

Rhythm at the next level

Syncopation puts an accent where the listener does not expect it, often by tying a note across a beat or by starting a phrase on an offbeat. A shuffle or swing feel divides each beat into a long and a short part rather than two equal parts. A triplet divides a beat into three equal parts. In 68, 98 and 12/8 the beat itself divides into three, which is what makes compound meter feel different from simple meter.

A hemiola is a temporary shift from three to two, or from two to three. In 68 a phrase can suddenly group the same six eighth notes as three groups of two, which sounds like 34. The notation may not change; the accent does. Counting the smallest value aloud is the surest way to feel it.

Simple meter:   1 and 2 and 3 and 4 and
Compound meter: 1 2 3 4 5 6
Triplet:        1 trip let 2 trip let

A short analysis example

Take a four-bar phrase in C major with the chords C, Am, F and G. The Roman numerals are I, vi, IV and V. The phrase begins on the tonic, moves to the relative minor, then to the subdominant, and ends on the dominant. If the next phrase returns to C, the cadence is authentic. If it stops on G, the cadence is half.

Bar 1:  C    melody E  D
Bar 2:  Am   melody C  B
Bar 3:  F    melody A  G
Bar 4:  G    melody F  D

The melody notes on the strong beats are chord tones: E in C, C in Am, A in F, G in G. The notes between them are passing tones. The phrase has a simple arch: it rises to A in the third bar and falls back to D in the fourth. That contour, not the individual notes, is what makes the phrase sound like a statement and an answer.

To analyse a passage, work in this order: key and scale, phrase boundaries, chords, cadence, motive, and texture. Name what you hear before you name what you see. The labels are useful only if they explain the sound.

Sight-reading strategy

Before you play a note, scan the page. Check the clef, the key signature, the time signature, the tempo and the repeat marks. Find the highest and lowest notes and the largest leap. Identify the hand position and any shifts. Mark the hard bars with a pencil.

Read the rhythm first, away from the instrument. Tap the pulse and count the subdivisions. Then read the pitches in small groups, not one note at a time. Look ahead one beat or one bar while your hands play what you have already read. If you make a mistake, keep going: stopping at every error teaches you to stop, not to read.

How to practise

Fifteen focused minutes are enough for most players. Spend five minutes on rhythm, five on intervals and chords, and five on reading a new piece. Sing the intervals before you name them. Play a chord and identify its quality by ear, then check the root and the voicing. Write Roman numerals above a simple score and compare your analysis with the sound.

Transpose a short melody into another key. The intervals stay the same, but the notes and the shapes change. This is the fastest way to connect theory to the fretboard, and it turns a page of rules into a skill you can use.

Where to go next

The guides on modes, scales and composition build on this material. Modes change the home note of a scale; composition turns intervals, chords and form into a piece. Learn the cadences and the diatonic chords first. They are the vocabulary that makes the rest of the language possible.