In the Spring and Autumn Period (chūn qiū 春秋时期,770-476 BC), Duke Huan of Qi (qí huán gōng 齐桓公) led an army to attack a small state in the north. They went in spring when green grass covered the ground. But when they came back it was winter. Everywhere was white with snow and the wind was howling. The troops lost their way. While everybody was worrying, Guan Zhong, the duke's chief minister, said: "An old horse may know the way." So the duke ordered several old horses to be choosed to lead the army. In the end, they found the way back home.This idiom refers to the value of experience.

Legend has it that there was once a water monster called Yu (yù 蜮). It had norns, a shell, wings and three legs, but no eyes. There was a catapult in its mouth. If Yu heard the steps of a man, it would shoot sand from its mouth at him. If even the mans’s shadow was hit, the man would fall ill.
This idiom indicates vilifying people by insinuation.

传说江淮间出产一种很特别的甲虫，名叫蜮，又有人称做射工、射影、短狐、水狐。这种虫常常伤害人，形状很是奇怪，背上长着硬壳，头上有角，身上长有翅膀，可以飞到上空，在人的头上施行袭击。它没有眼睛，但耳朵听觉特别灵敏，口中有一横物，形状像弩，只要听到人声便知道人的所在方向和距离，然后用口中所含的沙当作矢，向人射击。被蜮射中的人，会染上一种毒质而生疮；就算人的身体能够射避，而影子被蜮射中，也会生病。