Learning how to play the blues on guitar requires a bit of a "mind shift" in approach. Although there are a lot of similarities that can be found in rock, country and pop music - the aspiring blues guitarist would be wise to note that there are distinct differences that set the blues apart from other genres of music.One of those differences lies in the fact that many consider the blues to be the birthplace of rock and roll - and as you begin a study of blues guitar, the reasons will become apparent.
By acknowledging the fact that the blues preceded, and was in many ways the inspiration for, rock music - we as guitar players will quickly see that approaching the study of blues guitar as a separate and unique entity from other genres of music, is warranted.
To illustrate - the roots of many of the chord progressions commonly found in rock music today can be traced back to origins in early blues songs.
One example is the I, IV, V (one, four, five) chord progression. This chord progression is composed of the "first", "fourth" and "fifth" steps of the major scale, and is one of the cornerstones of blues music in general.
For example, a I, IV, V blues chord progression in the key of "E" would consist of the chords E, A and B.
In the key of "A", the chords would consist of A, D and E - and so on.
You can hear numerous examples of how this I, IV, V blues chord progression evolved into modern rock, country and pop song structures with songs like:
Johnny B. Goode - Chuck Berry (early rock and roll)
Honky Tonk Woman - Rolling Stones (rock)
Boot Scootin' Boogie - Brooks and Dunn (country)
This list could obviously go on and on.
As a result, the first step for the guitarist that wants to learn and master blues guitar would be to get a firm grasp on the I, IV, V chord progression, learn how to identify it, and how to play it in virtually any key.
Another blues guitar concept that evolved into rock, and other forms of music, is the lead scale used in blues guitar solos.
The dominant "blues scale" played in early blues music is roughly based on the minor pentatonic scale, with some variations.
The minor pentatonic scale, for example, in the key of "G" would look like this:
E-----------3------------6---------
B-----------3--------5-------------
G-----------3--------5-------------
D-----------3--------5-------------
A-----------3--------5-------------
E-----------3------------6---------
You could put this all together by playing a I, IV, V chord progression in the key of "G" (G, C and D), and play a lead solo over that progression by playing licks, riffs and runs based on the minor pentatonic scale in "G" as shown above.
And just like the evolution of blues chord progressions, the use of the minor pentatonic scale in soloing continued on (and still does) into rock guitar, as well as other genres such as pop, country and soul.
So it should become apparent that anyone wanting to learn blues guitar should begin with two simple steps:
1. Learn the I, IV, V chord progression - how it is used, what it sounds like, and how to play it in different keys.
2. Learn the minor pentatonic scale - memorizing the fingering pattern, knowing the root note, how to transpose it to various keys, and experiment with playing licks, riffs and runs within the scale.
As you can see, approaching the study of blues guitar as its own entity, separate and apart from other genres - will be well worth your time and efforts.
And the surprising irony is that, as you begin to learn and master blues guitar, you will find that the skills you develop as a blues guitarist will brim over and enhance your abilities as a rock, country, pop, jazz, or soul guitar player.