In Jianghu, like-minded people usually form brothers, which is called Jin Lan.
According to the Book of Changes, if two people are United, their profits will be cut off. Words of one mind stink like blue. It is about people who work together, and their strength can break axes and cut gold; People with one heart and one mind say a word together, which will make people willing to accept it like enjoying the fragrance from the orchid. From then on, orchids also have the meaning of referring to people who work together and are of one mind. The word Jin Lan first appeared in Shi Shuo Xin Yu. It is said that Shan Tao hit it off with Ji Kang and Ruan Ji, and the three of them hit it off very well, so they became half-brothers. The three of them have a very good relationship, which is described in this article as if they were like Jin Lan and as solid as gold. As a result, later generations called the act of becoming sworn as Jin Lan.
There are different ways to become sworn, but in the process of becoming sworn, other links can be omitted, and the only thing that cannot be omitted is the change of posts. Usually, people who become sworn should write their names, birthdates, places of origin, etc. on red paper and exchange them with each other. At the earliest, people called this exchange post "Jin Lan Spectrum". After the oath, according to birthdates written in "Jin Lan Spectrum", brothers are commensurate. Righteousness knot Jin Lan therefore called open.