Kosenkyo is the capital city of the New Yogo Empire. The city is situated on an alluvial fan between two arms of the Misty Blue Mountains; the Aoyumi River runs through the town.

The city is divided into three neighborhoods: Ogi no Shimo (Lower Ogi, meaning "the bottom of the fan"), which is a poor district; Middle Ogi, a middle-class district; and Upper Ogi, where the nobility live.

At the point of the fan, the royal palace is separated from the rest of the city by a wall. The palace consists of the First Palace (where the Mikado and the First Queen live), the Second Palace (where the Second Queen and Prince Chagum live), the Third Palace (where the Third Queen lives), and the Star Palace, where the Star Readers live and conduct their research.