The traditional East Asian calendars divide a year into twenty-four solar terms (節氣). Dōngzhì (Pīnyīn) or Tōji (Rōmaji), Đông chí (Vietnamese) (literally:winter's extreme) is the twenty-second solar term, and marks the winter solstice. It begins when the sun reaches the celestial longitude of 270° and ends when it reaches the longitude of 285°. It more often refers in particular to the day when the sun is exactly at the celestial longitude of 270°. In the Gregorian calendar, it usually begins around December 21 (December 22 East Asia time) and ends around January 5.