Regarding bichords, analyzed in the previous page, we could see how these are at the base of blues rhythmics, due also to the fact that the bichords themselves serve to elaborate the riffs, responsible for a majority of blues accompaniment. Continuing with this discussion, starting with the fifth and sixth bichords, we can verify that all you need is to add another note (the seventh flat) to subsequently emphasize the blues harmony. The seventh flat is contained in the mixolidian scale. Consequently it cannot be used in a blues riff.
As an example, it is best to use the scale of A, which we will use for the fingerings with the open chords, much easier with respect to the standard fingerings, which we will analyze later. Blues in A uses three basic chords: A7, D7 and E7. Using the bichords we can take advantage of the tones of the open chords, playing the other notes in the classical four fret position using the left hand. For the A bichord the fifth chord is open, the D bichord fourth, and the E bichord sixth. Look at the example below.

Obviously, from a harmonic point of view, the characteristics remain relatively unchanged for each scale. Now we can transport everything into the blues chorus, obtaining the accompaniment rhythm which can be seen below, and heard as a base midi.

In the other scales we won't use open chords, which will make the fingerings more complicated with respect to those already seen. In fact the extension of the fingers on the fretboard requires good agility due to the stretch that is required between the index and little finger. For the first few times, it is better to use high fingering positions. Lets try the C scale, using the fingerings in the eighth and tenth positions. The base midi is always helpful.

Now you should try to apply some of the lessons learned to assimilate a good dose of blues, using the riffs in the examples below. These are in a single scale, but should be used as often as possible for blues in other scales, in order to learn all the possible variations. For example, you can play example 1 in the tonal chord, example 2 on the fourth chord, example 3 on the fifth, to then vary the arrangements. Your "homework" can be completely personalized and is a useful educational tool.

As usual the octaves are shuffle. Note the presence of the tercets in exercises 3 and 4, which serve to give some variation to the rhythm. In the next page we will analyze the melody, in order to confront the first forms of blues improvisation.