The traditional East Asian calendars divide a year into 24
solar terms (節氣). 'Shuāngjiàng'
(pīnyīn) or 'Sōkō'
(rōmaji) () is the 18
th solar term. It begins when the Sun reaches the
celestial longitude of 210° and ends when it reaches the longitude of 225°. It more often refers in particular to the day when the Sun is exactly at the celestial longitude of 210°. In the
Gregorian calendar, it usually begins around
October 23 and ends around
November 7.