legal ground
Article 1065 of the Civil Code of People's Republic of China (PRC)
Both men and women may agree that the property acquired during the marriage relationship and the property before marriage belong to themselves, all or part of it, and part of it. The agreement shall be in writing. Where there is no agreement or the agreement is unclear, the provisions of Articles 1062nd and 1063rd of this Law shall apply.
Article 490
If the parties enter into a contract in the form of a contract, the contract shall be 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.
Article 502
A legally established contract shall come into force upon its establishment, except as otherwise provided by law or agreed by the parties.