The cello, like any string instrument, provides a challenge to players of all levels.  One area of difficulty involves mastering string positions corresponding with specific notes.  Some notes are produced on multiple strings, whereas other notes are produced on only one of the four strings.  To add complexity, the relative locations where notes are played differs among each of the four strings.  The Violoncello Reference Chart may be of assistance in determining positions of notes and visualizing relationships between notes.