GUIDO music notation

It was named after Guido of Arezzo, who pioneered today's conventional musical notation 1,000 years ago.

GUIDO was first designed by Holger H. Hoos (then at Technische Universität Darmstadt, Germany, now at University of British Columbia, Canada) and Keith Hamel (University of British Columbia, Canada).

Later developments have been done by the SALIERI Project by Holger H. Hoos, Kai Renz and Jürgen F. Kilian.

GUIDO Music Notation is designed as a flexible and easily extensible open standard.

Finally, Extended GUIDO can represent user-defined extensions, like microtonal information or user defined pitch classes.

Opening phrases of " O Sanctissima " 
[ \clef<"treble"> \key<"D"> \meter<"4/4">
 a1*1/2 b a/4. g/8 f#/4 g a/2 b a/4. g/8 f#/4 g
 a/2 a b c#2/4 d c#/2 b1 a/1 ]