A day traditionally honored as the day of the Buddha's enlightenment. While deep in meditation under a bodhi tree, he attained enlightenment upon seeing the morning star just at dawn; celebrated on the 8th day either of December or of the 12th month of the lunar calendar.
The word Rōhatsu is Japanese and literally means 8th Day of the 12th Month. It is typical for Zen monks and layman followers to stay up the entire night before Rohatsu practicing meditation, and the holiday is often preceded by an intensive sesshin. It is observed on the Gregorian date of December 8 as a result of the Westernization of Japan during the Meiji Restoration (1862–1869).