玄武，中国古代“四灵”之一。

　　　 关于它有两种不同的说法。其一，玄武就是龟，龟有甲，是武器，「玄武」之「武」由此而来。「玄」则指黑色。黑色代表北方。玄武即此方的神灵。其二，认为玄武是龟和蛇的合体。古人崇敬蛇，原因可能是古代龙和蛇不分。敬龟是因为龟乃长寿动物，传说中的神龟寿命长达几千年至一万年。古人认为龟具有先知先觉的本领

　　　Black tortoise / black union of tortoise and snake is one of the four spiritual creatures. （See below)　　

　　There are two sayings about Xuan wu. One is that Xuan wu is a tortoise because it has a shell as a weapon when it meet enemy. And it corresponds to the “wu” in the ‘Xuan wu”. “Xuan” means black in Chinese. So “Xuan wu” is just a black tortoise. It represents the north. The other is that “Xuan wu” is the union of the tortoise and the snake. Ancient Chinese people worshipped snake for its resemblance with dragon. And the tortoise is a long-lived animal. It is said that the supernal tortoise could live thousands years long. Also people thought it was able to foretell the future during that old and remote time.

四灵 The four spiritual creatures

　　“四灵”是中国人对动物的最古老的分类。人们根据动物的飞、走、行、游，羽、毛、鳞和天、地、水、土等性状特征及活动范围，将它们分成鸟、兽、虫、鱼四大类别，每类找一个代表，于是就产生“四灵”。同时， 四灵的形成又与古代天文学的发展联系在一起，殷代前后，古人把春天黄昏前后南方的若干星辰想像为一只鸟形，东方为一只龙形，西方为一只虎形，而北方为龟蛇形象。到了春秋战国，人们又将“四灵”标上了颜色，即青龙、白虎、朱雀、玄武。

　　Long long ago, ancient Chinese people sorted animals into four categories ( bird, beast, worm and fish ) according to their characters of flying, walking, moving , swimming , feather, plume , scale and their regions of living (sky, river, land ). Then they select one animal as representation of each category. This is the origin of the four spiritual creatures. With the development of the ancient astronomy, the four creatures were connected with star constellations and directions. About Yin dynasty, people thought that the configuration of star constellations in the east liked a dragon, south bird, west tiger and north the union of tortoise and snake. When it came to the Warring State , people added one color for each creature. From then on green/blue dragon( 青龙 ) ， white tiger ( 白虎 ) ， red bird ( 朱雀 ) and black tortoise/black union of tortoise and snake( 玄武 ) were frequently painted on the walls of the early Chinese and regarded as the four spiritual creatures of the celestial having the apotropaic function of warding off the evil spirits.