Learn the 12 Bar Blues Basic Structure

Follow this lesson on Jamtrackers for a more immersive experience:
https://jamtrackers.com/courses/ThOs2...

The 12 bar blues is a standardized chord progression. This "standardization" is what makes it a favorite for musicians when starting to jam. They are able to jump right in and start playing. All that is needed is to agree on the key, then the musicians will be able to know what, and when, chord changes occur.


The name "12 bar blues" is quite descriptive of what it is because the progression contains...12 bars!


Just a reminder: a bar in music, also known as a measure, is a segment of time defined by a given number of beats. Each bar is separated by vertical lines on the staff, and the number of beats in a bar is determined by the time signature. For the sake of simplicity, as we learn the 12 bar blues we'll say that each bar is 4 beats.


Below you can find a chart that counts out the 12 bar blues:


1 |2 |3 |4
5 |6 |7 |8
9 |10 |11 |12

For each of the numbers above you should count out in your head, "1-2-3-4".


Once we understand that there are 12 bars then we need to know what chords to play for each of those bars. Without yet choosing a key, we can have a look at the general chord progression pattern that the 12 bar blues follows. It is simple, as there are only 3 chords.


The 3 chords that are used in the 12 bar blues are the first (I), fourth (IV), and fifth (V) chords of the key scale that you are playing in.


The chart below has been updated to show the chord that is played in each bar:


I |I |I |I
IV |IV |I |I
V |IV |I |V

Now that we know the chord progression pattern, let's pick a key and assign the appropriate chords to each bar. When demonstrating the 12 bar blues I prefer to use the key of A major, which contains the following notes.


A, B, C#, D, E, F#, G#, A


Looking at this scale, we can see that the I note is A, the IV note is D, and the V note is E. Using these, we can fill out our chart in the following way:


A| A| A| A
D| D| A| A
E| D| A| E

Just like that, we are now able to play the 12 bar blues in the key of A major. There is still plenty to learn, but this is effectively enough to lay down some rythm guitar in a blues jam.


In the resources section I've provided some chord progressions that show the I, IV, V chords for some of the most common keys used in blues jams for beginners.