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<h1>Major Scales</h1>
<p>The major scale is the foundation of Western tonal music. Every key, every key signature, every diatonic chord progression starts here. If you know your major scales in all twelve keys, you have the framework that everything else hangs on — modes, chord tones, extensions, and voice leading all derive from knowing where the notes are and how they relate.</p>

<h2>Construction</h2>
<p>A major scale is seven notes built from a specific pattern of whole steps (W) and half steps (H):</p>
<pre>
W — W — H — W — W — W — H
1   2   3   4   5   6   7   (8=1, octave)

Half steps occur between scale degrees 3-4 and 7-8 (7-1).
</pre>
<p>The pattern works from any starting note. C major produces no sharps or flats. Every other root requires sharps or flats to maintain the W-W-H-W-W-W-H spacing.</p>

<h2>All Twelve Major Scales</h2>

<table>
  <thead><tr><th>Key</th><th>Notes</th><th>Sharps/Flats</th></tr></thead>
  <tbody>
    <tr><td>C major</td><td>C D E F G A B</td><td>None</td></tr>
    <tr><td>G major</td><td>G A B C D E F#</td><td>1# (F#)</td></tr>
    <tr><td>D major</td><td>D E F# G A B C#</td><td>2# (F#, C#)</td></tr>
    <tr><td>A major</td><td>A B C# D E F# G#</td><td>3# (F#, C#, G#)</td></tr>
    <tr><td>E major</td><td>E F# G# A B C# D#</td><td>4# (F#, C#, G#, D#)</td></tr>
    <tr><td>B major</td><td>B C# D# E F# G# A#</td><td>5# (F#, C#, G#, D#, A#)</td></tr>
    <tr><td>F# major</td><td>F# G# A# B C# D# E#</td><td>6# (+ E#)</td></tr>
    <tr><td>C# major</td><td>C# D# E# F# G# A# B#</td><td>7# (all)</td></tr>
    <tr><td>F major</td><td>F G A B♭ C D E</td><td>1♭ (B♭)</td></tr>
    <tr><td>B♭ major</td><td>B♭ C D E♭ F G A</td><td>2♭ (B♭, E♭)</td></tr>
    <tr><td>E♭ major</td><td>E♭ F G A♭ B♭ C D</td><td>3♭ (B♭, E♭, A♭)</td></tr>
    <tr><td>A♭ major</td><td>A♭ B♭ C D♭ E♭ F G</td><td>4♭ (+ D♭)</td></tr>
    <tr><td>D♭ major</td><td>D♭ E♭ F G♭ A♭ B♭ C</td><td>5♭ (+ G♭)</td></tr>
    <tr><td>G♭ major</td><td>G♭ A♭ B♭ C♭ D♭ E♭ F</td><td>6♭ (+ C♭)</td></tr>
  </tbody>
</table>

<h2>Key Signature Rules</h2>
<pre>
Order of sharps: F C G D A E B   (each new sharp key adds one more)
Order of flats:  B E A D G C F   (reverse of sharps)

Sharps: the key is one half step above the last sharp.
  G major: 1# (F#) → key is one half step above F# = G ✓

Flats: the key is the second-to-last flat.
  B♭ major: 2♭ (B♭, E♭) → second-to-last flat = B♭ ✓
  (C major is the special case: no flats, no sharps)
</pre>

<h2>The Diatonic Chords</h2>
<p>Build a triad or seventh chord on each scale degree using only notes of the key. The chord quality pattern is the same in every major key:</p>

<table>
  <thead><tr><th>Degree</th><th>Numeral</th><th>Quality</th><th>In C major</th><th>Function</th></tr></thead>
  <tbody>
    <tr><td>1st</td><td>I</td><td>Major 7th</td><td>Cmaj7</td><td>Tonic — home, resolved</td></tr>
    <tr><td>2nd</td><td>ii</td><td>Minor 7th</td><td>Dm7</td><td>Subdominant — movement away from tonic</td></tr>
    <tr><td>3rd</td><td>iii</td><td>Minor 7th</td><td>Em7</td><td>Often substitutes for tonic</td></tr>
    <tr><td>4th</td><td>IV</td><td>Major 7th</td><td>Fmaj7</td><td>Subdominant — strong contrast</td></tr>
    <tr><td>5th</td><td>V</td><td>Dominant 7th</td><td>G7</td><td>Dominant — strongest pull to tonic</td></tr>
    <tr><td>6th</td><td>vi</td><td>Minor 7th</td><td>Am7</td><td>Relative minor — tonic-like quality</td></tr>
    <tr><td>7th</td><td>vii°</td><td>Half-diminished (m7♭5)</td><td>Bm7♭5</td><td>Dominant function, leading tone chord</td></tr>
  </tbody>
</table>

<h2>Circle of Fifths</h2>
<pre>
Moving clockwise: add one sharp each step
Moving counter-clockwise: add one flat each step

    C (0)
F(1♭)     G(1#)
B♭(2♭)   D(2#)
E♭(3♭)   A(3#)
A♭(4♭)   E(4#)
D♭(5♭)   B(5#)
    G♭/F#(6♭/6#)

Adjacent keys (one step apart) are closely related — modulations between them
sound natural because they share six of seven notes.
</pre>

<h2>Relative and Parallel Relationships</h2>
<pre>
Relative minor: built on the 6th degree of the major scale.
  C major → A natural minor (same notes, different tonal centre)
  G major → E natural minor
  
Parallel minor: same root, different key signature.
  C major (C D E F G A B) → C minor (C D E♭ F G A♭ B♭)
  Parallel keys produce modal interchange — borrowing chords across the parallel.

The major 7th chord (I) is the most stable, at rest.
The dominant 7th (V) is the most active, pulling back to I.
This tension and resolution is the engine of tonal music.
</pre>

<h2>Intervals Within the Major Scale</h2>

<table>
  <thead><tr><th>Scale degree</th><th>Interval from root</th><th>Semitones</th><th>Example (C)</th></tr></thead>
  <tbody>
    <tr><td>2nd</td><td>Major 2nd</td><td>2</td><td>D</td></tr>
    <tr><td>3rd</td><td>Major 3rd</td><td>4</td><td>E</td></tr>
    <tr><td>4th</td><td>Perfect 4th</td><td>5</td><td>F</td></tr>
    <tr><td>5th</td><td>Perfect 5th</td><td>7</td><td>G</td></tr>
    <tr><td>6th</td><td>Major 6th</td><td>9</td><td>A</td></tr>
    <tr><td>7th</td><td>Major 7th</td><td>11</td><td>B</td></tr>
    <tr><td>Octave</td><td>Perfect octave</td><td>12</td><td>C</td></tr>
  </tbody>
</table>

<h2>References</h2>
<ul>
  <li>Levine — <em>The Jazz Theory Book</em></li>
  <li>Aldwell &amp; Schachter — <em>Harmony and Voice Leading</em></li>
  <li><a href="https://www.musictheory.net/lessons/21" target="_blank" rel="noopener">musictheory.net — Key Signatures ↗</a></li>
</ul>
