The yo scale, which is like the Dorian but does not contain minor notes, according to a traditional theory is a pentatonic scale used in much Japanese music including [1] gagaku and shomyo. The yo scale is used specifically in folk songs and early popular songs and is contrasted with the in scale which does contain minor notes. [2] The in scale is described as more 'dark' while the yo scale is described as 'bright' sounding. [3]
It is defined by ascending intervals[ clarification needed] of two, three, two, two, and three semitones. An example yo scale, expressed in western pitch names, is: D - E - G - A - B. This is illustrated below.
The Ryūkyū scale appears to be derived from the yo scale with pitches raised. [4]
More recent theory [5] emphasizes that it is more useful in interpreting Japanese melody to view scales on the basis of "nuclear tones" located a fourth apart and containing notes between them, as in the min'yō scale used in folk music, and whose pitches are equivalent to the second mode of the yo scale: [6]
In India's Carnatic music, this scale corresponds to Udayaravichandrika.