Which Key?

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This gets a bit wordy, so if you’re into light reading, you might want to click away now!

My current interest is in the blues. If you’re playing blues guitar, you may never play a major scale in your life, but you should know what they are if you’re ever going to play in more than one key. The blues is usually based on some variation of a 12 bar pattern that repeats over and over. I’m probably not telling you anything new there.

The 12 bars are usually based on a I-IV-V configuration that consists of 4 measures (bars) of the I chord, 2 measures of the IV chord, 2 measures of the I chord, one measure of the V chord, one measure of the IV chord and 2 measures of the I chord. That is probably the most simple pattern and the reason for this article is not the pattern. If you’re reading this, you probably already know about the variations in the 12 bar pattern.

So what is a I-IV-V chord sequence anyway?

Simply put, I-IV-V is the I chord (or the root chord). This is also the key that the song is in.
The IV is the chord based on the 4th note in the major scale of the 1 note (confused yet? It hopefully gets easier).
The V is the chord based on the 5th note in the major scale of the 1 note.

So… First, let’s look at the C Major Scale, since it is undoubtedly the easiest one to follow. The C Major scale consists of 8 notes. They are:
C – D – E – F – G – A – B – C. ? The last C is the C that is one octave higher than the first one.

This means a 12 bar blues in the key of C uses the chords I = C, IV = F, V = G.
Simple, eh?

Major Scales
The construction of a major scale isn’t logical, but since birth, virtually every piece of western music you have heard has been based on it.

So, you know what the major scale is supposed to sound like almost by instinct.
It’s the Do-Re-Me-Fa-So-La-Ti-Do you probably were taught in elementary school.
It starts on Do, or what you call the 1 note. Fa is the 4 and So is the 5.
Not very helpful since no musical instrument has any of these notes.

They aren’t really notes, but instead they are intervals between notes.
You can’t know what Re sounds like without first hearing Do.
Do is the root or the I. But enough about that. It is a combination of notes and the intervals between the notes that make up the major scale.

Major Scale Construction.

Interval W W H W W W H
Note 1 2 3 4 5 6 7 8

So, now you know how the major scale is built. Which notes make up the major scale?

The answer is, it depends on what your 1 note is.

Quick and dirty… You can memorize this and go no further.
You will be able to play the 12 bar blues in any key you like. The 1 note is the I chord and it is also the key in which the song is played.

Interval W W H W W W H
Note 1 2 3 4 5 6 7 8
Key Of: C D E F G A B C No Sharps, No Flats
Key Of: G A B C D E F# G One Sharp, F#
Key Of: D E F# G A B C# D Two Sharps, F# C#
Key Of: A B C# D E F# G# A Three Sharps, F# C# G#
Key Of: E F# G# A B C# D# E Four Sharps, F# C# G# D#
Key Of: B C# D# E F# G# A# B Five Sharps, F# C# G# D# A#

For the Flat keys it works like this.

Interval W W H W W W H
Note 1 2 3 4 5 6 7 8
Key Of: C D E F G A B C No Sharps, No Flats
Key Of: F G A Bb C D E F One Flat, Bb
Key Of: Bb C D Eb F G A Bb Two Flats, Bb Eb
Key Of: Eb F G Ab Bb C D Eb Three Flats, Bb Eb Ab
Key Of: Ab Bb C Db Eb F G Ab Four Flats, Bb Eb Ab Db
Key Of: Db Eb F Gb Ab Bb C Db Five Flats, Bb Eb Ab Db Gb

More to come in the next post!

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