In Japanese culture, a hatsuyume (Japanese: 初夢) is the first dream one has in the new year. Traditionally, the contents of such a dream would foretell the luck of the dreamer in the ensuing year. In Japan, the night of December 31 was often passed without sleeping, so the hatsuyume is often experienced during the night of January 1; the day after the night of the "first dream" is also known as the hatsuyume. This day is January 2 in the Gregorian calendar, but was different in the traditional Japanese calendar.