For microtonally retuned piano was a commission by Sanae Yoshida.
This piece's primary source of inspiration was a book with the same title on the music theory from the 13th century written by Safiaddin Ormavi (1211 Urmia -1294 Baghdad).
The rough translation of the title would be the book of circles, which was how Ormavi did notate the music. Ormavi illustrates modes in the form of circles and calls them Dawr (while Advār represents the plural form).
In "Ketāb al-Advār", Ormavi developed and proposed a theoretical system of a 17-tone gamut to describe the music of his time that could cover Persian, Arabic & Turkish music. In his system, the tones are not equally spaced. It is also essential to notice that this gamut has never functioned as a scale but as a set of pitches ordered uniquely. It gave the possibility of constructing independent scales but primarily functioned separately from the concept of scale.
Safiaddin Ormavi proposed 84 different musical modes, organized into two groups: consonance and dissonance (for a further and more detailed explanation, please visit: REVISITING THE MEDIEVAL TREATISES ON IRANIAN MUSIC). According to his system, only twelve out of 84 modes can be considered consonances and are simultaneously the primary modes for creating instrumental music.
Below: Dawr Ushshāq, as illustrated in Ormavi's system, shows the internal relationship of the intervals within the mode Ushshāq.