Eight-bar blues

An eight bar blues is a typical blues chord progression, taking eight 4/4 bars to the verse.

A basic example of the progression would look like this, using T to indicate the tonic, S for the subdominant, and D for the dominant, and representing one chord per beat:

(The same chord progression can also be called a sixteen-bar blues, if each symbol above is taken to be a half note in 2/2 or 4/4 time -- blues has not traditionally been associated with notation, so its form becomes a bit slippery when written down.)

Many variations are possible. For instance, seventh chords are often used just before a change, and more changes can be added. A more complicated example might look like this, where "7" indicates a seventh chord:

When the last bar contains the dominant, that bar can be called a turnaround.

Finally, here is an example showing the pattern in the key of D, and how it fits with the lyrics of a given verse. One chord symbol is used per beat, with "-" representing the continuation of the previous chord:

twelve bar blues, chord progression.