Four types of triads music notated in harmonic positions with detailed fingering notation that suite the best the left hand. The triads are harmonized with four differnt voicing derived from the triads itself. Thinking double notes motion is a powerful practice which bring your musical skill on a higher plateau. Practicing this subject in all keys will benefit the undersatnding of the guitar board and harmony, enriching your playing with an elegant and refined device. Great for improvisation or arrangment porpouse. Fourteen pages work.