The Twelve Bars

Almost every blues you have ever heard is the same twelve bars, repeated. Learn to feel where you are in those twelve bars and you can sit in with strangers, in any key, without anybody telling you the chords.

The form uses only three chords, named by their position in the key. In the key of A those are A (the I chord), D (the IV chord) and E (the V chord). Count four beats to a bar, twelve bars to a chorus, and then it starts again.

Here is the standard layout, one chord per bar: A, A, A, A, D, D, A, A, E, D, A, E.

That last bar of E is the turnaround. It is the sound of the form pulling you back to the top, which is why it feels unfinished if you stop there.

The only thing to practise in this lesson is counting. Play nothing at all the first time through. Just count 1-2-3-4 twelve times and say the chord name out loud as each bar arrives.

12-Bar Blues Metronome

Set the key to A and let it count the form for you — it calls the changes out loud and shows the chart for each chord as it arrives.

Run the metronome slowly, around 70 beats per minute, and count along until you can predict the change to D in bar 5 before the metronome tells you. That anticipation is the whole skill.

When counting feels automatic, put it against a real band.

A straight 12-bar blues in A. Don't play yet — just count the twelve bars and follow the chord changes as they light up.