Hardback book, read in the late 1980s, involving a wandering samurai investigating a cat demon tearing peoples' throats out around a village

Question

I'm pretty sure I found this again several years ago, and learned it was a series, but I first read it when I was in elementary school (although I think it was supposed to be for older readers). The main character is a samurai in Japan. I don't know if he'd been sent by someone, or if he was doing it on his own, but the village that the story is set in has had a rash of killings where people have been found with their throats torn out, with the eerie yowl of a cat heard from a distance. I think the actions in the book happened during winter because I have a vague memory of one of the fights happening in the middle of a snow storm, maybe connected with the assumption of supernatural events since the victims were apparently killed when no one was around according to the tracks.

It turns out that the killer is a former samurai, known to the protagonist, maybe his brother, who'd had his throat severely damaged, causing him to emit the catlike yowl. He was killing people with a grappling hook, explaining the throats torn out with no tracks nearby. When he is found out, the protagonist allows him to commit seppaku, serving as his second to cut off his head after he had sliced his belly open (this was the first time I'd heard of this form of ritual suicide, so it made a big impression on me).

I don't remember any details about the cover or the author, but I do remember it as a hardback book, probably over a hundred pages. It might have still been marketed as a kid's book, but I was dipping into the adult section of the library at an early age, so I can't swear to that.

Answer 1

Ah, I found it via TV Tropes and their Hooks and Crooks entry. Village of the Vampire Cat is the fourth book in the Zenta and Matsuzo mystery series by Lensey Namioka, published in 1981.

When Zenta and Matsuzo, two masterless samurai, arrive at the home of Zenta's old friend and former teacher, the two discover that the village has been tormented by an unknown force. A mysterious killer, known as the Cat because of his sharp claws, has already killed four young girls, now Zenta and Matsuzo must solve the mystery and put an end to the terror. Zenta and Matsuzo are wondering ronin (masterless samurai) with a skill and code of honor unlike the ordinary citizens of Japan. Together the stoic Zenta and carefree Matsuzo fall in and out of extraordinary adventures-solving mysteries that leave others baffled. Set in sixteenth century Japan, the books in the Zenta and Matsuzo Mystery series present unique and complex plots that are full of action, intrigue, and suspense.

According to the Kirkus review:

The culprit turns out to be Ikken's sword-master son, not killed three years back but hideously disfigured . . . and not only nursing a grievance against the villagers but loco about Asa, to whom he'd been engaged. In the wind-up, Ikken and son Shunken both commit hara-kiri, freeing Zenta and Matsuzo--more one-dimensional than in previous episodes--to go on to new challenges.