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Parsons code - Wikipedia

The Parsons code , formally named the Parsons code for melodic contours , is a simple notation used to identify a piece of music through melodic motion movements of the pitch up and down. Denys Parsons developed this system for his 1975 book The Directory of Tunes and Musical Themes . Representing a melody in this manner makes it easier to index or search for pieces, particularly when the notes values are unknown.