Recognised on 1 October annually, Nihonshu no hi 日本酒の日 (International Sake Day), is know as sake day. It marks the first day of the sake-making season.
The main reason is related to the character written for SAKE. The old symbol for sake is 酉, in the form of a jar, and 酉 in Chinese character, signifies the 10th year, the 10th month and the 10th hour in a cycles of 12 in the Chinese Zodiac. After harvesting, sake-making begins in the fall, usually in October, the 10th month of the year; and the first day of October has been set by the sake industry as “Sake Day” in 1978.
The current symbol for sake is 酒：
ミ represents liquid / wine
酉 represents jar