Oktoechos

(in Russian, osmoglasie), a system used in composing music for the Orthodox liturgy. It originated in the Byzantine Empire after the fourth century in connection with certain hymn texts. Eight modes, or echoi (glasy), formed a table that was repeated several times in the course of a year. Subsequently there arose national variants, each having its own particular features.

Russian oktoechos is of greatest significance for the znamennyi chant. Each of the znamennyi chant’s eight modes is characterized by its own set of popevki (short motifs). The modes do not represent unified harmonic systems; in one mode there may be popevki with endings on different notes of the scale. The number of popevki in a mode ranges from 150 to 300, and some popevki are common to several modes. Ordinarily, liturgical music is composed in one mode. Occasionally, however, transitions are found from one mode to another. Even in the 20th century the Russian church retains oktoechos, although it also makes use of other, unrelated, forms of liturgical music.