Can the "prior art" (ie, the prior art known to the applicant) specified by the patentee in the specification be considered "common general knowledge" at the time of filing? Further, is it possible to determine the technical ability of a person ordinarily skilled in the art through the prior art specified in the specification? The Supreme Administrative Court has explicitly taken a negative stance in response to these questions.


To determine the validity of a patent, it is often necessary to determine the technical ability of a person ordinarily skilled in the art so as to ascertain whether:

  • the claimed invention can be easily accomplished; or
  • the specification meets the requirements of definiteness and full disclosure.(1)

In practice, the person "ordinarily skilled in the art" refers to a hypothetical person who has "general knowledge" and "ordinary skill" in the art of the claimed invention at the time of filing.

"General knowledge" includes:

  • well-known knowledge in the art, as disclosed in textbooks or reference books; and
  • commonly used information and things that can be understood from general rules.

"Ordinary skill" means the ordinary ability to perform routine work and experiments.

Consequently, general knowledge and ordinary skill at the time of filing are cumulatively referred to as the "common general knowledge at the time of filing".(2)


In a 2021 judgment, the Court stated:

Although the Taiwan 0000000 and 0000000 invention patents were specified in the 'prior art' paragraph on pages 4 and 5 of the patent at issue, the contents specified indicate that the two cited invention patents are the prior art that the patent at issue intends to improve. Since they are not textbooks or reference books but prior art only in nature, it is hard for the prior art to be considered common general knowledge at the time of filing the application of the patent at issue. The appellant has a misunderstanding that the two patents are known technologies only because they are recorded in the specification of the patent at issue.(3)


In view of the above, even if the patentee states in the specification that the particular prior art is well known, whether it is the common general knowledge of a person ordinarily skilled in the art – in pursuance of the determination criteria of general knowledge and ordinary skill – must still be objectively determined.

For further information on this topic please contact Shih-I Wu at Lee and Li Attorneys at Law by telephone (+886 2 2763 8000) or email ([email protected]). The Lee and Li Attorneys at Law website can be accessed at


(1) See article 22(2) and article 26(1) of the Patent Act.

(2) See Article 14 of the Enforcement Rules of the Patent Act, and Part II, Chapter 2, Section 2.3 of the Guidelines for Determination of Patent Infringement.

(3) 2021 Shang Zi No. 172.