In all my years of teaching guitar, one of the most theoretical and essential lessons to learn and grasp quickly are the important differences between all the various blues notes and chords.

When one starts to utilize the various pentatonic scales, it becomes quite apparent that after awhile certain “outside” or “passing” notes become necessary to stretch these scales and their potential. What happens is there is a whole new array of licks and phrases that are born out of these notes being added, and the possibilities are endless.

When first hearing the term “tenth” in music, it may seem baffling, but it’s simply a way to tell you that we have now jumped an octave over the initial eight notes of the scale. It’s really an interval in 3rd that now contains a note that is substituted by a higher or lower note, octave-wise. This is how a 2nd can become a 9th, for example. In this case, a 3rd becomes a 10th. This is just some basic theory dealing with the mathematical relationships of notes.