Chrysanthemum Day, also known as Kiku no Sekku, is observed in Japan every September 9. This cultural festival celebrates the chrysanthemum, a symbol of the Imperial House of Japan, which is featured on the Imperial Seal and associated with the Chrysanthemum Throne. The festival's origins date back to 910, when the first chrysanthemum show was held by the Japanese imperial court during early autumn, as the flower is considered seasonal at that time. Chrysanthemum Day is closely related to the Chinese Double Ninth Festival and was historically celebrated on the 9th day of the 9th lunar month before the adoption of the Gregorian calendar. Today, the festival is marked with colorful flower shows at Buddhist temples and Shinto shrines across Japan, although it is not recognized as a public holiday.