This Luna is pre grinded after the last heating process. This is done, after the last heating process, but before fine tuning, since the grinding detunes the instrument. The reason for grinding is because this one was requested in fire-red laquering. Since the metall starts to oxide in the process of heating, the coroding layer darkens the surface of the metall. After grinding the light steel appears again, wich is neccesary for the used Kijomi Urushi to appear in a cherry-reddish color and give it additional depth, because the light is reflected two times - one time from the laquer surface & one time from the metall surface.