The twelve-bar blues, in B♭
The twelve-bar blues in B♭ uses B♭7 (I7), E♭7 (IV7) and F7 (V7).
The progression lasts twelve bars and uses three different chords, and everything below is played over it. The notes of your scale stay the same from bar to bar, but each chord agrees with a different set of them. Every chord is a dominant seventh, which is why this sounds like the blues rather than music in a single key. Each chord contains a major 3rd that your scale does not, and that clash is the sound of the blues.
Where to land in B♭ minor pentatonic
- land a note of the chord, so a phrase that stops here sounds finished
- your root B♭, the root of your scale rather than of the chord, and every number on the neck is a degree counted from it
- bend a place to land, a semitone below the chord's 3rd, so bend the string up into it
- pass in your scale but not in the chord, so move through it on the way to a chord tone
- leans a semitone above a chord tone, so it wants to fall onto that tone
Over B♭7, land on scale degrees ♭7, 1 and 5. D belongs to the chord but not to B♭ minor pentatonic. Over E♭7, land on scale degrees 1, ♭3 and 4. G belongs to the chord but not to B♭ minor pentatonic. Over F7, land on scale degrees 4 and 5. A and C belong to the chord but not to B♭ minor pentatonic.
Position 10 is drawn once for each chord. Your hand stays in the same place, but the notes worth landing on change with the chord.
Now play it
- Loop the twelve bars slowly, or play along with a backing track that uses them.
- Play one note in each bar and nothing else. Choose a filled dot each time, and let it ring until the chord changes.
- Over F7, try B♭, the root of your scale, and hold it. It is the note you are most likely to fall back on, yet over that chord it wants to fall away onto the chord tone a semitone below, which is what the tick means.
- Over B♭7, land on D♭ and push it up a little. It sits a semitone below the chord's 3rd, and bending it up by that semitone is the sound of the blues.
- When that feels easy, join the notes up into phrases. Then turn on the chord's own notes and find D over B♭7. It is one fret from a note you already know, and it is the note that separates your scale from the chord.
A single note in each bar sounds like very little, but it teaches you more than a hundred notes would. What matters is not the note itself but hearing the chord arrive underneath a note you chose before the chord did.