Legal analysis: multiple contracts can't have only one riding seal, and each contract needs to be stamped with a complete contract seal. Where a natural person enters into a contract, the natural person entering into the contract shall sign or affix his own name and seal; When a legal person or other organization concludes a contract, the legal representative of the legal person or the person in charge of the other organization shall sign or affix the official seal or contract seal of the company. If the parties conclude a contract in the form of a contract, the contract shall be established when both parties sign or seal it.

Legal basis:

Article 490 of the General Principles of the Civil Law of People's Republic of China (PRC) stipulates that if the parties conclude a contract in the form of a contract, the contract is established when the parties sign, seal or press their fingerprints. Before signing, sealing or fingerprinting, one party has fulfilled its main obligations, and the contract is established when the other party accepts it.