12 Bar Blues is a pattern of chords which repeats every 12 bars. There are hundreds of well known songs based on this chord progression, i.e., they contain basically the same chords in the same order. 12 Bar Blues is one of the most common progressions in Blues, Jazz and Rock. Every harmonica player will be regularly asked to play a 12 Bar Blues. In fact it is very likely to be the first kind of song used at any jam session. The following example demonstrates a common 12 Bar Blues riff played on the harmonica. A riff is a pattern of notes which repeats and may be altered slightly to fit the chords.
One of the classic sounds in Blues music is the combination of harmonica and guitar. When you play any riff or melody on a 12 bar Blues progression, your notes are fitting in with a specific set of chords which can be played by a guitar (or keyboard). The chords most commonly played by the guitar are built on the first, fourth and fifth notes of the key you are playing in. These chords are often described by the use of roman numerals. If you are playing in the key of C, these chords will be C (1), F (4) and G (5). A detailed explanation of notes and chords as scale degrees is given in Lessons 11 and 12. The easiest way to start recognising the relationship between notes and chords is to remember that each time you begin playing a riff on a C note (hole 1, 4 or 7 exhale), the guitar will most likely be playing a C chord, which is simply the C note with two additional notes on top of it. When the note and chord are played together, a harmonious sound is produced. In the following examples, chord symbols for the chords C, F and G are written above the notation to show which chords a guitar would play to accompany the harmonica. The basic pattern of the 12 bar Blues is shown below.
Here is a variation on the previous 12 bar Blues riff, this time using eighth notes. Since there are no longer notes in this example, you will need to take a quick breath at the end of every second bar.
This is an eighth rest. It indicates half a beat of silence.
All the chords in this example are played on the and (+) part of the count.
This 12 Bar Blues makes use of both quarter and eighth rests. The only notes in this example are C, F and G, which are the notes on which the chords for a 12 bar Blues in the key of C are built.
Here is another Blues using eighth rests. This one is a rhythm part which works well with a guitar or a whole band.