This week's exoneration of a former boxer over a quadruple murder in 1966 and a lawsuit filed by the former chairman of a publishing company in recent months have put Japan's "hostage justice" system back into the spotlight.

Former Kadokawa Chairman Tsuguhiko Kadokawa, who has consistently maintained his innocence amid accusations of bribery, filed the lawsuit in June to challenge the controversial system, in which suspects are often denied bail unless they confess to the crimes they are accused of.

Human rights groups argue that the system creates a breeding ground for false convictions.