Seishi Yokomizo is one of the most famous and prolific Japanese mystery novelists, and The Village of Eight Graves is one of his most famous works, with countless adaptations in various forms of media. It's filled with death, as one might hope for a murder mystery, yet it feels like it might be trying to make up for quality with quantity. I found the book... underwhelming. It wasn't bad, but it felt more like a spooky suspense story than an orthodox detective plot, and a lot of the more distinctive plot elements have been better utilized in other works (although I acknowledge that The Village of Eight Graves might have been the book to pioneer those plot elements).
The Eighth Detective
Mystery fiction presents an interesting challenge. There are certain conventions or "rules" governing the genre—including a literal set of ten commandments (and another ruleset double that)—and yet, from one point of view, the ultimate goal is to surprise and shock the reader, while remaining within the "rules." Obviously, no one is putting a gun to someone's head to obey these rules (well, maybe in a story they do), and some of mystery fiction's most famous and celebrated works break these conventions. So they're more like guidelines. There's no reason you can't just say a wizard did it, but doing that will result in an unsatisfying resolution. (Usually.)
The Eighth Detective is a short story collection that aims to expand the "rules" of mystery fiction by providing a comprehensive definition of a murder mystery and a series of stories that illustrate this definition. It's pretty underwhelming. I think this is because the central conceit suffers from a critical flaw: the formula that The Eighth Detective is built around tells you whether a piece of fiction is a murder mystery or not, but has absolutely nothing to say about whether it's good.
The Eight of Swords
Mysteries should take advantage of their premise. If the story takes place in a unique setting, then the solution should involve a trick that's only possible in that particular location. If the hook of the crime is a unique or bizarre state of the crime scene, then there should be a compelling reason the crime scene was in that state.
In The Eight of Swords, the culprit leaves an Eight of Swords at the crime scene. Quite easy to understand, no? That tarot card is one of the main draws of the book; after all, it's what the novel is titled after! And yet... there's no compelling reason for that card to be there. Heck, I have absolutely no idea why the culprit left the card there, other than to provide a clue to Dr. Fell to use to deduce their identity.
The 8 Mansion Murders / 8の殺人
The title of The 8 Mansion Murders is way too generous; there's no way I'd rate it anywhere close to an eight. It's not particularly clever or inspired, but seems to think it's some sort of epoch-defining masterpiece.