Daseian notation

These eighteen pitches are based on a system of four repeating tetrachords, resulting in the following scale: G A B♭ c | d e f g | a b c' d' | e' f♯' g' a' | b' c♯''.

When it is used to construct polyphonic music, as directed in the treatises, it results in a number of written tritones, which were considered undesirable by theorists in performance and were probably mistakes of the author or else implied the system was transposable to C D E♭ F | G A B♭ c | d e f g | a b c' d' | e' f♯' or d e f g | a b c' d' | e' f♯' g' a' | b' c♯'' d” e” | f♯'' g♯'' when necessary.

If the pitch changed, the word syllables would be raised or lowered to a different staff line.

[7] This would continue until the development of the widely used staff system of Guido of Arezzo in the eleventh century.

Philipp Spitta was the first modern musicologist to correctly interpret this notation, in an 1889 publication.