《史记·七十列传·货殖列传》
善于将时与用二者相对照，那么各种货物的供需行情就能看得很清楚。所以，岁在金时，就丰收；岁在水时，就歉收；岁在木时，就饥馑；岁在火时，就干旱。
计然曰： 知斗则修备，时用则知物，二者形则万货之情可得而观已。故岁在金，穰；水，毁；木，饥；火，旱。
If one is good at comparing the relationship between time and use, then one can clearly see the supply and demand market conditions of all kinds of goods. Therefore, in the metal year, there will be a good harvest; in the water year, there will be a bad harvest; in the wood year, there will be a famine; in the fire year, there will be a drought.