The original script was a police drama with minimal action.
Although credited as the sole writer, Harold Nebenzal's script was rewritten before filming by producer Pancho Kohner and director J. Lee Thompson to make the material more like a Charles Bronson movie.
According to the book "Charles Bronson" by Michael R. Pitts, the meaning and relevance of this movie's title is that it "refers to subjects (such as sex, child molesting, prostitution) which are forbidden topics in Japanese culture."
The word Kinjite comes from the Japanese language and is the "-te" conjugation form of the verb "kinjiru"; which means "to forbid" in English.