Diatonic scale are major scales (those with a major third/triad: Ionian, Lydian, and Mixolydian), three are minor (those with a minor third/triad: Dorian, Phrygian, and Aeolian). To these may be added the seventh diatonic scale, with a diminished fifth above the reference note, the Locrian scale. These could be transposed not only to include one flat in the signature (as described by Glarean), but to all twelve notes of the chromatic scale, resulting in a total of eighty-four diatonic scales. The modern musical keyboard originated as a diatonic keyboard with only white keys. The black keys were progressively added for several purposes:
Insen scale Insen scale Insen (or In Sen) is a tuning scale adapted from shamisen music by Yatsuhashi Kengyō for tuning of the koto. It only differs from the hirajoshi scale by one note. In D mode it consists of: D-E-G-A-C so it has the same notes as the Phrygian chord (7sus♭9). Other chords compatible with insen scale include M7♯11 when the scale is played half steps lower (for example B in sen scale for CM7♯11 chord) and Cm6 and Cm when the scale is played one full step above (for example D insen with Cm6 or Cm chord). Other scales related