📖 Theory Guide

What is a staff?

Music is written on a staff — 5 lines and 4 spaces. Notes sit on the lines or in the spaces. The higher the note on the staff, the higher it sounds.

Treble Clef (𝄞) — right hand / higher notes

The treble clef curls around the G line (second from bottom) — that's why it's also called the G clef.

Bass Clef (𝄢) — left hand / lower notes

The bass clef's two dots surround the F line (fourth from bottom) — also called the F clef.

Middle C

Middle C sits on a short ledger line below the treble clef or above the bass clef. It's the C in the middle of the piano — a great landmark note!

Accidentals

Note values (in 4/4 time)

Dotted notes

A dot after a note adds half of that note's value to it.

Rests — silence

Every note value has a matching rest (silence). The semibreve rest hangs from the 4th line; the minim rest sits on the 3rd line.

The time signature appears at the start of a piece. It tells you:

🔝 Top number = how many beats per bar
🔽 Bottom number = what note gets one beat (4 = crotchet, 8 = quaver, 2 = minim)

Simple time Grade 1

Compound time Grade 2

Cut time Grade 3

Order of sharps & flats

Major key signatures

Scale patterns

Every major scale follows the same pattern of Tones (T = whole step) and Semitones (S = half step):

Harmonic minor scale Grade 2

The harmonic minor raises the 7th degree by a semitone, creating an augmented 2nd (3 semitones) between degrees 6 and 7. This gives it an exotic, dramatic sound!

How to count an interval

Count every letter name from the bottom note to the top note, including both notes.

Example: C → G = C(1) D(2) E(3) F(4) G(5) = a 5th.

Interval quality Grade 2+

Recognise intervals by song

Every interval has a famous song that starts with it. Train your ears!

Building a triad

A triad is a 3-note chord built by stacking 3rds: root, 3rd, 5th.

Inversions Grade 3

Primary triads Grade 3

The three most important chords in a key are built on the 1st, 4th and 5th degrees:

Cadences Grade 3

Tempo (speed)

Dynamics (volume)

Expression & style

→ Practice all terms with flashcards 📚

What is a cadence?

A cadence is a pair of chords that ends a phrase — like a musical full stop or comma. The chord built on each degree of the scale has a Roman numeral:

Perfect Cadence — V → I G1

The perfect cadence (also called an authentic cadence) goes from chord V to chord I. It sounds finished — like a musical full stop.

Plagal Cadence — IV → I G1

The plagal cadence goes from chord IV to chord I. It sounds gentle and settled — softer than a perfect cadence.

Imperfect Cadence — ends on V G3

An imperfect cadence ends on chord V. It sounds unfinished — like a musical comma, leaving you expecting more.

Interrupted Cadence — V → VI G3

The interrupted cadence (also called a deceptive cadence) goes from chord V to chord VI — a surprise! You expect V → I, but get VI instead.

Quick summary

→ Practice identifying cadences in Chord Game 🎹

The 6 strings

A standard guitar has 6 strings. From the thickest (lowest pitch) to the thinnest (highest pitch):

Reading chord diagrams

Chord diagrams show the guitar neck from the front:

• Vertical lines = strings (left = low E, right = high e)
• Horizontal lines = frets
• ● dots = where to press your finger
• O above a string = play it open (unfretted)
• ✕ above a string = don't play this string
• A number above the dots = which finger to use (1=index, 2=middle, 3=ring, 4=pinky)

Common open chords

These are the essential beginner chords — all playable without barre (pressing across all strings):

→ Practice guitar chords with the quiz 🎸

How chords relate to piano theory

The chord names are the same! A G major chord on guitar has the same notes (G, B, D) as on piano — just played differently. All the music theory you learn for piano applies to guitar too.