The year 2600 in the imperial calendar refers to the series of commemorative events held in 1940 (Showa 15) to celebrate the 2600th anniversary of the enthronement of Emperor Jimmu (Imperial Era). This appears to be a postcard sold at the celebratory art exhibition held at that time. While there is some fading due to age, it is in beautiful condition with almost no stains. There are 12 postcards in the set. If you are interested, please check the images and consider purchasing.