Sekigan no Shoujo

Sugaru, a remote village that doesn’t even appear on any maps. In this village, there were daughters of a family that inherited the power of a god for more than a thousand years. They were called "Sugaru-sama" and ruled the village for generations.

In 1985, a girl who was a candidate to be Sugaru-sama's successor is found dead with her head cut off. Detective Misasagi Mikage, a beautiful girl with a jade left eye wearing a suikan, takes on the case. Mikage, whose mother is a legendary detective, discovers facts that the police have overlooked one after another and seems to be getting to the bottom of the matter. However, the case produces a second and a third victim...

(Source: Bungeishunju, translated)