Ritsu and ryo scales
The "ritsu" and "ryo" scales are anhemitonic pentatonic scales -- five-note scales without semitones -- used in a type of Japanese Buddhist chant called shōmyō. The "ritsu" scale is built up by intervals of major second, minor third, major second, major second, minor third, while the "ryo" scale is major second, major second, minor third, major second, minor third. A third scale called "Hanryo hanritsu" is created by combining the "ritsu" and "ryo" scales however there is no agreed way to combine the two. The ritsu scales do not fit exactly into the equal temperament prominent in  Western classical music but "ritsu" is transposable to E and B, "Ryo" is transposable to D and G, and "Hanryo hanritsu" to A. The Ritsu scale is one of the six scales (along with the major and minor scales, the common pentatonic scale, and the common "blues" scale) that provide more consonant harmonic intervals than any other possible scales that can be drawn from the 12 semitones of equally tempered pitch. Esoteric significance. The "ritsu" scale is the voice of the male phoenix, yang, being, the voice that ascends from above and is inhaled breath, emerging from the "ki" while  the "ryo" scale is the voice of the female phoenix, yin, nothingness, the voice that ascends from below and is exhaled breath, emerging from the breath; probably indicating that "ritsu" is vertical and "ryo" is horizontal.