I thought the Chinese Chengdu J-7 was a copy of the Soviet MiG-21 (even the NATO names are similar with Fishcan and Fishbed, respectively). This was but the first of many misconceptions put to rest by author Holger Müller. As stated in the Introduction,

The development of the Chinese MiG-21 derivatives is not only an interesting technological history in itself, but also reflects the changes in the politics of the People’s Republic of China (PRC) on a smaller scale: from its alliance with the Union of Soviet Socialist Republics (USSR) to rapprochement with the West and the PRC’s own path of state capitalism.