秋分是二十四节气的第十六个节气，南方的气候由这一节气起才开始入秋。按我国古代以立春、立夏、立秋、立冬为四季开始的季节划分法，秋分日居秋季90天之中，平分了秋季。今年的秋分始于9月23日。
秋分当日太阳直射地球赤道，昼夜长度相等。此后，阳光直射位置开始进入南半球，北半球开始昼短夜长，气温降低。秋分节气已经真正进入到秋季，作为昼夜时间相等的节气，人们在养生中也应注意保持阴阳平衡。
秋分曾是传统的祭月节。如古有
“春祭日，秋祭月”之说，现在的
中秋节则是由祭月节而来。据考证，
最初祭月节是定在秋分这一天，不
过由于秋分当日不一定都有圆月，
而祭月无月又大煞风景，所以后来
就将祭月节由秋分调至中秋。
投壶是古代秋分节气期间宾主宴饮时盛行的游戏。方法是:设一壶，使宾主依次向壶内投矢，胜者倒酒给败者喝，大致与乡射相同。所不同的是，投壶用手掷，不是以弓射。投掷的是标而不是箭，命中的是壶而不是靶。
俗语有“秋分到，蛋儿俏”的说法。在秋分时节，人们会选择刚生下四五天、且光滑匀称的新鲜鸡蛋，然后轻轻地将鸡蛋竖立在桌子上。据史料记载，秋分竖蛋的习俗出现在四千年前的中国，如今，竖蛋玩法已传到世界上的许多地方。
俗话说，“秋分食蟹忙”。秋分时节是蟹肉最肥美、也最滋补的时候。螃蟹属上等名贵水产，肉嫩味美。不仅如此，螃蟹还有极高的营养价值。螃蟹性寒，食用螃蟹不宜过多，最好搭配暖性食物一起进食，如姜茶或黄酒。
在岭南地区，秋分时节有个不成节的习俗叫做“秋分吃秋菜”。秋菜是一种野觅菜。逢秋分那天，全村人都去采摘秋菜。采回的秋菜一般与鱼片滚汤，名曰“秋汤”。有顺口溜道：“秋汤灌脏，洗涤肝肠。阖家老少，平安健康。”
The traditional Chinese lunar calendar divides the year into 24 solar terms. Autumn equinox, the 16th solar term of the year, begins on Sept 23 this year and ends on
Oct 7.  Autumn equinox lies at the midpoint of autumn, dividing autumn into two equal parts.
As it is said in the ancient book The Detailed Records of the Spring and Autumn Period (770-476BC), "It is on the autumn equinox day that the yin and yang are in a balance of power. Thus the day and night are of equal length, and so are the cold and hot weather."
Originally, moon sacrifices ceremony was held on autumn equinox, but since dates are not fixed on lunar calendar, sometimes the moon was not full. The ceremony is meaningless without a full moon and moon sacrifices ceremony was subsequently moved to Mid-Autumn Day (Oct 3 this year). 
In ancient China, people threw arrows into pots to welcome autumn equinox. Hosts would invite guests to throw arrows into a pot at a distance with their hands. Players whose arrows failed to make the pot had to drink wine as a punishment.
On the day of autumn equinox, there are thousands of people in the world trying to make eggs stand on their ends. This Chinese custom has become a game of the world. Eggs that are 4 or 5 days old are best for this game. 
Autumn is the season for hairy crabs. Crabs from Yangcheng Lake of East China's Jiangsu province are widely acknowledged as the best kind of hairy crabs. Hairy crabs are "cool" in nature, thus it is advised to consume them with something "warm" in nature, such as ginger tea.
Having qiucai (autumn vegetable) on autumn equinox is a custom in South China.  Qiucai, a kind of wild amaranth, is often stewed with fish into qiutang, or autumn soup. 
 
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