This exercise is from my new book Classical Guitar Technique: Essential Exercises, Scales, and Arpeggios. The 122 page book includes: Practice Routines, Tips, 100 Open String Exercises, 120 Giuliani Arpeggios, Scales, Slur Exercises, Shifts, Finger Independence, Barre, Tremolo, Common Harmonics, and much more.
Scales in 3rds, 6ths, Octaves, and 10ths – There are an endless number of exercises for finger independence and stretching but playing scales in various intervals provides an excellent workout and adds musical context and variety. Since this is not a scale encyclopedia I’ve limited the number of exercises to major scales with one page for each interval. I’ve written out all the scales in solid form but also practice in broken form.
Why are the bass notes in 6ths not the root of the scale (in C Major in 6ths why is C not the bass note)? Using inverted 3rds (which are 6ths) allows the harmonic progression of triads to stay intact. So the chords in Roman numerals are I, ii, iii, IV, V, vi, vii°, I (capitals being major and small being minor). So that C and E in the bass in the first interval is a C major chord, the D and F from the next one is a D minor chord etc. This is harmonically pleasing and makes the connection to the natural harmonic progression in the key of C.