September 9 is Choyo-no-sekku, or Chrysanthemum Festival.
Odd numbers are regarded as active numbers, and number 9 is the ultimate active number. September 9 is therefore a matter of congratulation as dual 9 is the highest level of activeness. September 9 in the lunar calendar is in the season when chrysanthemum is in full bloom and is thus referred to as Chrysanthemum Festival, when people wish for longevity by viewing chrysanthemum flowers and tasting chrysanthemum sake.
Chrysanthemum is originally a symbol of grandeur and one of the flowers that represent Japan. It is not only beautiful to the eye but also has been used as a Chinese medicine and valued as food since ancient times.
Chrysanthemum sake is made with edible mum flowers soaked in sake for about a month, but the off-the-cuff version of it with mum petals added to the glass is equally enjoyable. Quickly boiled chrysanthemum flowers are crisp and also delicious.