The cold cases mentioned in this chapter:
they make for an interesting read to be honest 🙂
The Shimoyama incident: 1949 - involved the disappearance and death of Sadanori Shimoyama the first president of Japanese National Railways
https://en.wikipedia.org/wiki/Shimoyama_incident
Teigin case: 1948 - Cyanide poisoning of bank employees
https://en.wikipedia.org/wiki/Sadamichi_Hirasawa
Soka Jiro (aka Kusaka Jirō) incidents: 1962/1963 - Crimes of varying degrees (bombs, sniper attacks, etc.) where the culprit left the name "Soka Jiro" behind.
(could only find link in french and japanese) https://ja.wikipedia.org/wiki/%E8%8D%89%E5%8A%A0%E6%AC%A1%E9%83%8E%E4%BA%8B%E4%BB%B6
Glico Morinaga case: 1984/1985 - Kidnapping and extorsion
https://en.wikipedia.org/wiki/Glico_Morinaga_case