There was an alternative tonal system used in the Northern Slavic reception in Novgorod, which was based an a hexaechos, since it used a tone system based on triphonia with three modes organised in fourth equivalence.
There was an alternative tonal system based on the "obihodniy zvuhoryad" which was used in the Northern Slavic reception in Novgorod. It was based an a hexaechos, since it used a tone system based on triphonia with three modes organised in fourth equivalence.