The derkach is a folk percussion-noise instrument of the ratchet type. Its construction is simple and ingenious: a wooden cogged cylinder and a flexible tongue-lath in a frame; when the instrument is spun, the tongue clatters over the cogs, producing a characteristic sharp rattling sound.
In the Ukrainian tradition the derkach has a special ritual significance during Holy Week before Easter: in those days, when by church custom the bells fall silent, ratchets were used to summon the faithful to the church in place of the bell. It was also used by children in folk games, by shepherds, and by musicians for a rhythmic noise effect. Similar rattles are known to many peoples of the world, but the Ukrainian derkach remains a vivid element of folk ritual and of the soundscape of the traditional village.
