Hanami, or admiring cherry blossoms, is the most beloved and well-known tradition of the Japanese. It is believed to have originated in the Heian period, 794-1185. The official opening of the Sakura flowering season takes place in the Central Park of Tokyo in the presence of the Imperial couple. Hanami is almost the only day of the year when citizens are willing to take time off from work early in order to spend more time in the parks. They are often visited by the whole team from work, arranging a kind of corporate parties. Among the most popular appetizers are rice balls and sake.