EDOGAWA Rampo is doubtless the most famous crime writer in Japan; but the most famous detective is probably YOKOMIZO Seishi's (横溝 正史 1902-1981) KINDAICHI Kousuke. ICHIKAWA Kon made several very successful films of the Kindaichi books; and the manga series Shounen Kindaichi no Jikenbo ("The Case Files of Young Kindaichi") are written to suggest that the teenage hero is the great detective's grandson. Kindaichi is an eccentric private detective, shabbily dressed in traditional Japanese clothing (at a time when men more or less always wore western clothing), stuttering or scratching through his untidy hair when excited, accustomed to make an odd impression on those he meets, for which he typically gives an amused half apology. Most of the stories featuring him are set in the aftermath of the Second World War, when they were written, but 本陣殺人事件 (Honjin satsujinjiken, The Honjin Murder Case), though published in 1946, is set before the war.
In the Edo period, the Ichiyanagi family ran a honjin, an official guesthouse for travelling representatives of the shogunate; and they are still a family of tradition and influence in the Okayama country where they live. (Yokomizo came from this area, and many of the books are set there or in the neighbouring Inland Sea.) On the night of the wedding of the elder son of the family to the daughter of a new rich businessman, the couple are found stabbed with a sword in a house which is completely locked from the inside. The koto that had been played on the wedding night rang out again at the murder; and a search of the red walled room in which the couple died finds the fingerprints of a three fingered man.
Most Kindaichi books are very long, but this is short (200 pages in my edition, which adds two novellas). Oddly while the long novels seem to need room to build up atmosphere and character, "The Honjin Murder Case", to my taste, does as good a job in what would be a short novel even by western standards. The puzzle elements are more prominent than in some of the other books; and there are some good tricks in there. I don't think I'd rank the locked room particularly high; but there my taste in impossible crimes seems to be the same as victim's brother, an enthusiast for locked rooms.
You can read other bloggers' reactions to the book here and here.
The two novellas both have a postwar setting: 黒猫亭事件 (Kuronekotei jiken, The Black Cat Café Case) is much more modern than "The Honjin Murder Case". As a puzzle, I can't have much enthusiasm for it. It reads like one of those pieces where the writer started with a trick and then tried doing the carpentry to provide a reason to use it, but gave up half way. A humorous metaliterary introduction, in which Yokomoizo and Kindaichi discuss detective story conventions like the disfigured corpse is more interesting than the actual story. The other, 車井戸なぜ軋る (Kurumaido naze kishiru, Why did the well pulley creak?), is actually my favourite. Kousuke Kindachi only appears in the prologue and epilogue, and apparently was added after the original publication. The core story is a series of letters from a young woman to her brother, who is in a nearby sanatorium, describing the events in the house since their elder brother has returned from the war, blind and with face injuries. Returning veterans crop up in several Kindaichi books; and if you've read or seen "The Inugami Clan", you'll recognise the similarity (you could see this story as a rehearsal for the other). There's the same question whether the returning soldier really is the brother. But written from the viewpoint of the sister, the question is more directly felt; and the experience of civilians alienated from a family member, who seem to have come back from war a different person, adds to the atmosphere. Yokomizo doesn't try to dot the i's and cross the t's of the puzzle; but I don't think that anyone would complain about the mystery.