Tenmado (koji room skylight)

Tenmado (skylight) is a type of ventilation device installed in the ceiling of a koji room (koji muro), where it helps regulate the temperature and humidity inside. In sake brewing in particular, temperature control is important for maintaining the quality of the koji. By opening and closing the tenmado, brewers can maintain an appropriate environment suited to the outside weather and keep the koji fermentation process running smoothly. In this way, the tenmado is an essential element of koji making and contributes to the success of sake brewing.