01Note Names & Duration

Western music uses seven letter names — A B C D E F G — that repeat every octave. On a piano, the pattern of white and black keys repeats every 12 keys; the distance from one note to the same note above is an octave (a 2:1 frequency ratio). The black keys are named with a sharp (♯) — a semitone up — or a flat (♭) — a semitone down. So the key between C and D is both C♯ and D♭ (they are enharmonic: same pitch, two spellings).

A note's duration is shown by its shape. Each value is half the length of the one before it:

A dot after a note adds half its value again (a dotted half = 2 + 1 = 3 beats). A tie is a curved line joining two notes of the same pitch into one longer sound (quarter tied to quarter = 2 beats). A triplet squeezes three equal notes into the space of two.

02Rests & Pauses

A rest is a measured silence. Every note value has a matching rest of the same length, so rhythm is a mix of sound and calculated silence — the silences are as important as the notes.

Rests can be dotted and tied by the same rules as notes. A whole rest hangs below a staff line; a half restsits on top of one — a handy way to tell them apart.

03Clefs & the Staff

Notes are written on a staff — five lines and four spaces. A clef at the start fixes which pitches those lines and spaces mean.

Notes above or below the staff use short ledger lines to extend it. Middle C is the shared reference point that links the treble and bass staves.

04Music Notation

The written page carries far more than pitch and rhythm. The core symbols:

Accidentals — a ♯ raises a note a semitone, a ♭ lowers it, and a ♮ (natural) cancels either. An accidental lasts to the end of the bar.

Key signature — sharps or flats placed right after the clef that apply for the whole piece, so you don't rewrite them every bar. (See the Circle of Fifths for how these are ordered.)

Bar lines divide music into measures (bars). A double bar marks a section; a final bar (thin + thick) ends the piece. Repeat signs ‖: … :‖ enclose music to be played twice.

Beams connect the flags of eighth/sixteenth notes into groups so the beat is easy to read. Slurs (a curve over different pitches) mean play smoothly/legato; a tie (same pitch) extends duration.

05Time Signatures

The two stacked numbers after the clef define the meter. The top number = how many beats per bar; the bottomnumber = which note value gets one beat (4 = quarter, 8 = eighth, 2 = half).

06Dynamics & Articulation

Dynamics are how loud or soft to play — Italian terms, softest to loudest:

A crescendo (<) gets gradually louder; a decrescendo / diminuendo (>) gets softer. Articulationshapes each note: a staccato dot = short and detached; a tenuto line = held full length; an accent(>) = play it stronger; a fermata (𝄐) = hold longer than written.

07How Notes Relate

The smallest distance in Western music is the semitone (half step) — one key to the very next, black or white. Two semitones make a whole tone (whole step). Scales and chords are built almost entirely from patterns of these two steps.

Notes that sound stable and blended together are consonant (octaves, fifths, thirds); notes that create tension wanting to resolve are dissonant (seconds, sevenths, the tritone). Music is largely the craft of moving between tension and release. Because of enharmonic equivalence the same key can be named two ways (G♯ / A♭) — which spelling you use depends on the key and the harmony around it.

08Intervals

An interval is the distance between two notes, measured in semitones and named by a number (how many letter names it spans) plus a quality: Perfect (P), Major (M), minor (m), Augmented (A) or diminished (d). Unisons, 4ths, 5ths and octaves come in perfect form; 2nds, 3rds, 6ths and 7ths come major or minor.

09Scales, Keys & Modes

A scale is an ordered set of notes within an octave. The major scale is the reference point — a fixed pattern of whole (W) and half (H) steps:

Major: W – W – H – W – W – W – H  (C D E F G A B C)

The minor family comes in three flavors:

A key is a home base — a scale plus the sense that its first note (the tonic) is "home." Every major key has a relative minor that shares its notes (C major / A minor).

Modes

Play the white keys but start on a different note and you get a mode — same notes, new center, new mood:

Pentatonic scales use just five notes (major or minor) — the backbone of folk, rock and blues melodies because none of the notes clash.

10Chords

A chord is three or more notes sounded together, built by stacking thirds. The three-note core is a triad: root, third and fifth.

Add another third on top for a 7th chord, and keep stacking for extensions (9th, 11th, 13th):

11Chord Inversions

A chord keeps its identity no matter which note is on the bottom. Moving the lowest note up an octave gives an inversion — same chord, different bass, smoother voice-leading.

A triad has 3 positions (root, 1st, 2nd); a 7th chord adds a third inversion (7th in the bass); a 9th chord a fourth, and so on — one inversion per chord tone. In lead sheets an inversion is written as a slash chord: C/E means a C chord with E in the bass. Classical figured bass writes the same idea as 6 (first inversion) or 6/4 (second).

12Circle of Fifths

Move clockwise and each step is a perfect fifth up, adding one sharp; counter-clockwise adds flats. It maps every key signature, shows each major key beside its relative minor (inner ring), and puts closely-related keys next to each other — the essential chart for keys, transposition and chord progressions.

13Jazz Harmony

Jazz treats the theory above as raw material for reharmonization and improvisation. A few pillars:

Seventh chords are the default — plain triads are rare; everything is at least a 7th, usually with 9ths, 11ths and 13ths added for color. The engine of the style is the ii–V–I: in C that's Dm7 – G7 – Cmaj7, the most common cadence in the repertoire.

Voicings drop or omit notes so the important tones (the 3rd and 7th, the "guide tones") lead smoothly from one chord to the next; the root is often left to the bass. Soloists think in chord-scales — Dorian over a m7, Mixolydian over a dominant 7, Lydian over a maj7 — choosing a scale for each chord. Swing feel turns straight eighth notes into a long-short triplet lilt, and tritone substitution swaps a V7 for the dominant a tritone away (G7 → D♭7) for a chromatic bass line.

14The Blues

The blues is a form and a feeling that underpins jazz, rock, R&B and soul. Its skeleton is the 12-bar blues, built from just three chords — the I, IV and V, almost always as dominant 7ths:

Melodically it leans on the blues scale — a minor pentatonic with an added flat-5 "blue note": 1 ♭3 4 ♭5 5 ♭7 (in C: C E♭ F F♯ G B♭). The magic is playing these flattened, expressive notes against major-leaning dominant chords — the friction between the two is the sound of the blues. Bends, slides and call-and-response phrasing complete the language.