China has never had an intellectual property law. In ancient times, how was the craft and technology kept secret?

The purpose of intellectual property law is not to monopolize technical secrets, but to protect the great economic benefits generated by inventors' inventions. Article 1 of the General Provisions of the Patent Law of People's Republic of China (PRC): This Law is formulated for the purpose of protecting the legitimate rights and interests of patentees, encouraging inventions and creations, promoting the application of inventions and creations, improving innovation ability, and promoting scientific and technological progress and economic and social development. Before the Qing Dynasty, inventors had to protect their own rights and interests because the state had no laws to protect their rights and interests. The main means are technology monopoly, technology blockade, behind closed doors, and only passing secrets to family successors. The patent system requires inventors to disclose your invention.