"Countersignature" refers to the official seal, seal, signature seal or other seals on agreements, treaties, contracts and other documents signed between two or more individuals and organizations, which are used to express the recognition and unified opinions of two or more parties. Generally speaking, this color printing style is the design of two organizations, including the name of the organization, the name of the legal representative, the date of signature and so on. Seal is a legal agreement, which has legal effect and is of great significance to safeguarding the rights and interests of both parties.

In ancient China, the concept of palm-to-palm was used for cultural exchange, compilation of historical books and the sealing of most governors. For example, Forty-two Chapters Classic is the largest collection of books in the world, which was mainly compiled by Daoan and his descendants during the reign of Xiaochang in the Northern Qi Dynasty. There are 733 chapters in Liang and Tang Dynasties, which is one of the important treasures of China's ancient "cultural exchange". In addition, many princes and ministers also designed their own poems and characters on their seals to show their cultural accomplishment and status.

In modern business transactions, "antithesis" is often used. In international trade, there is a common way called "descriptive seal", that is, two or more big seals are used in the contract and signed by all parties. This can strengthen the trust of both parties and ensure the legitimacy of the contract. At the same time, in the financial industry, real estate transactions can also adopt the method of chapter. In short, no matter what industry, it is of great significance to the club.