On the back panel of the refrigerator. According to the official online store information of Panasonic refrigerator, the bar code of Panasonic refrigerator is on the back panel of refrigerator, with 20 digits, the seventh from the bottom is the year of manufacture, the sixth from the bottom is the month, and the fifth from the bottom is the day, from 1-9 represents the date 1-9, and from 10 it is represented by a, 16544.