A man and a woman are discovered dead on a beach in Southern Japan, in each other's arms. The local police conclude it is a love suicide, and put the case to bed.
However one local cop is not convinced: if the couple were lovers why did they not stay in the same hotel? What prompted their deaths after five days in the quiet seaside town? If they were lovers, why did only one of them eat dinner on the long train journey from Tokyo? And does the scandal surrounding the ministry for which the man worked explain his motive for death?
The detective, and his opposite number in Tokyo work together to unpick the circumstances of the deaths, and in particular to unravel the seemingly solid alibi of their main suspect (an alibi based on train times and unimpeachable witnesses). The book is a true police procedural, as we follow the thoughts of the detectives through their investigations until the final resolution.
The book is not long, and the translation to English is very well done. Written in 1970, but the book is not dated (although the modern reader will be more ready to think of ways to move quickly between locations than the heroes do).
By chance I found a book by Seichoo Matsumoto translated to English in a book-shop in Tokyo. Now I want to read all I can find translated to languages that I understand. A brilliant author who writes detective stories of highest quality, yes, literature of highest quality.