I wrote a review of half of the 1982 book Suspicion (疑惑) by MATSUMOTO Seichou a year ago. That was the novella with the book title. Somehow I didn't get round to reading the other half of the book, the novella,不運な名前 (fuunna namae, An Unfortunate Name, first published separately in 1981).The story is an investigation of a famous counterfeiting case from the 19th century, presented as fiction, much like Josephine Tey's The Daughter of Time (1951).
The story's setting is the museum of the old Kabato Prison in Tsukigata, Hokkaidou. The prison was set up as part of the Meiji government's efforts to populate Hokkaidou; the prisoners were to provide a workforce to build the necessary infrastructure. The most famous prisoner was perhaps KUMASAKA Chouan (熊坂 長庵, 1844-1886), arrested for forging Japanese banknotes. The case was notable because three years before Kumasaka's arrest, the businessman FUJITA Denzaburou (藤田傳三郎, 1841-1912) and other leaders of the Fujita group had been taken into investigative custody on suspicion of being the culprits, then finally released without charge. The suspicion had been a major scandal, involving senior politicians, and many have suspected that Kumasaka was a scapegoat, especially as his name was only one letter different from a famous Heian period robber, 熊坂長範 (KUMASAKA Chouhan).
The investigators in the story are three visitors to the prison museum: a freelance writer investigating the case (we see everything through his eyes and thoughts); a retired teacher and passionate defender of Kumasaka's honour; a young woman, apparently a tourist. Although the scene and the modern characters are given a personality, they are really only there to mediate the narration and analysis of the nineteenth century story. The actual case is interesting, but it's not easy reading. In several places we have long excerpts from Meiji era documents and narratives; and even when the modern characters are speaking, they constantly reference outdated and technical terminology. I must admit that I'm a fairly recalcitrant reader for most popular history in general, and this sort of fictional account in particular. I suspect the whole time that the writer is working more like a lawyer advocating a case than a researcher. The status as fiction is particularly problematic when much of the argument is based on a photograph of a forged note in the private possession of the fictional freelance writer.
From the Wikipedia page on Kumasaka, I see that this is not the first time Matusmoto had written about the case. There's a 1964 story 相模国愛甲郡中津村 (Sagaminokuni Aikougun Nakatsumura) which is apparently based on the case (the title is Kumasaka's home village); but I haven't read it.