legal basis
article 65 of the patent law of the people's Republic of China
in accordance with the provisions of article 45 of the patent law, a request for invalidation or partial invalidation of the patent right shall be submitted to the patent reexamination board in duplicate. The request for invalidation shall, in combination with all the evidence submitted, specify the reasons for the request for invalidation and indicate the evidence on which each reason is based.
Article 68
The Patent Reexamination Board shall send a copy of the request for invalidation of the patent right and relevant documents to the patentee, requiring him to state his opinions within a specified time limit.
Article 7
The Patent Reexamination Board may, at the request of the parties concerned or the needs of the case, decide to conduct an oral hearing on the request for invalidation.