Okina (meaning “old man”) masks are the earliest of all Noh masks.
It’s worn only for “Okina”, a Noh play that is also a Shinto ritual.
The chin is separated and attached by string which is a feature particular to the Okina mask.
It is a mask that predates the establishment of Noh itself, a shape that isn’t found in other masks.
“Okina” is a play with no story or lines, instead consisting only of a series of ritual chants.
Because of this, Okina masks are regarded as sacred and
treated very carefully as if objects of worship themselves.