Blues Guitar Chords:12-Bar Blues Structure
The distinctiveness aspect of blues song structures isn’t so much that there are any special blues guitar chords, unlike say funk where certain chord shapes and rhythm patterns tend to be used then others. Instead, a structure known as the 12-bar blues is used to note the tonality of any particular bar within the song. This makes for some easy songs for guitar because it becomes a matter of knowing when to plug in what might only be three different bars into the music structure, as opposed to the need for a long lesson of song construction theory from a blues guitar lesson.
Basic 12-Bar Blues Structure
The most basic structure of the 12-bar blues is:
This pattern repeats either for the duration of the song, or sometimes for only part of the song if the song contains multiple structures (something not as common in purely blues songs, but more common in blues influenced songs which incorporate this structure). This sort of structure is easy for even someone just learning how to play lead guitar to play over because of the lack of any problematic chords that could create major tonal conflicts.
Each bar usually denotes four beats since most blues songs use 4/4 construction. The particular tonality in relation to the key of the song is the one emphasized or played in a particular bar. For a song in the key of A, the emphasized noted would be A (I), D (IV), and E (V). This is either done by playing the particular chords, or sometimes by using a riff that focuses on that particular note. The kinds of chords can vary based on the guitarist since there is no uniform set of blues guitar chords.
While this structure creates some very easy songs for guitar and is commonly seen in blues guitar lessons, this basic structure isn’t used very often. The reason is quite simple and becomes apparent on playing through it a couple of times. This is that on repeats of the structure, there are six bars in a row of the (I) chord, which means half the song is literally the same thing repeated over and over without any changes to tonality.
Adding a Turn Around
The easiest way to alleviate this is simply by changing the last bar into what is often referred to as a “turn around.” This usually creates a structure as shown below:
By replacing the (I) chord in the twelfth bar, there is no longer six (I) chords in a row. The turn around usually is a very distinct riff or rhythmic progression, which gives the listener a very distinct idea of the end of a musical phrase. In many respects is used like the period at the end of a sentence, a distinct and understandable end to an idea. This also removes the somewhat less prominent issue of the twelve bar blues to slur together rather than have repetitions sound like distinct musical ideas.
Using this basic structure, a guitarist can make a wide variety of easy songs for guitar, possibly by incorporating bars of music to which they are familiar with from other blues guitar lessons. Don’t be afraid to incorporate ideas from other styles of guitar, the important aspect of this structure is to preserve the tonality rather than to use a set of special blues guitar chords. Almost anything outside complex chords holds some potential to be incorporated in this structure and maintain the bluesy feel.