Among alternative tunings for the guitar, an overtones tuning selects its open-string notes from the overtone sequence of a fundamental note. An example is the open tuning constituted by the first six overtones of the fundamental note C, namely C2-C3-G3-C4-E4-G4. Music theorist William Sethares has discussed an overtones tuning that uses six higher partials, from fourth to ninth, of the overtone sequence; his tuning is not an open tuning.