 There were several unsuccessful attempts to classify the tones of Chinese before the establishment of the traditional four-tone description between 483 and 493.It is based on the Vedic theory of three intonations (聲明論).The middle intonation, ', maps to the "level tone" (平聲); the upwards intonation, ', to the "rising tone" (上聲); the downward intonation, "", to the "departing tone" (去聲).