Biswanath Prasad Radhey Shyam v Hindustan Metal Industries

• Respondent held a patent for a brass pitcher with a specific shape and process
• Appellant manufactured similar pitchers and was sued for infringement
• Appellant challenged validity on grounds of lack of inventive step
• Evidence showed similar pitchers were manufactured by craftsmen before the patent date
• Expert evidence was led on obviousness

1. What constitutes an inventive step for a valid patent
2. Whether a workshop improvement satisfies the inventive step requirement

• A patent must disclose something not obvious to a person skilled in the art
• A workshop improvement (routine variation by a skilled craftsman) is not patentable
• Patent revoked for want of subject matter
• Test: would a skilled person, knowing the prior art, consider the step obvious?

The inventive step is the dividing line between invention and craftsmanship. Prior art includes all publicly available knowledge. If the variation is what any competent worker would produce routinely, there is no invention.