"Life is like a masked ball. All men and women live their lives wearing masks."
"The Masked Ball" (Yokomizo Seishi)
And again, a disclosure message just to be sure: I translated the English version of Ayatsuji Yukito's The Decagon House Murders last year, which is part of the same series as the book I'm discussing today.
Yakata series (Author: Ayatsuji Yukito)
Jukkakukan no Satsujin (The Decagon House Murders) 
Suishakan no Satsujin (The Water Mill House Murders) 
Meirokan no Satsujin (The Labyrinth House Murders) 
Ningyoukan no Satsujin (The Puppet House Murders) 
Tokeikan no Satsjin (The Clock House Murders) 
Kuronekokan no Satsujin (The Black Cat House Murders) 
Ankokukan no Satsujin (The Darkness House Murders) 
Bikkurikan no Satsujin (The Surprise House Murders) 
Kimenkan no Satsujin (The Strange Masks House Murders) 
The first time mystery writer Shishiya Kadomi met horror writer Hyuuga Kyousuke, he thought he had finally found his doppelgänger. Their resemblance becomes useful when Hyuuga is invited by the wealthy Kageyama Itsushi to attend a secret meeting. The monetary reward for his time is something Hyuuga can't refuse, but a sudden illness prevents him from going. Hyuuga therefore asks Shishiya to go in his place (pretending to be Hyuuga), so they can share the money. Shishiyai doesn't feel much for the scheme, until he learns that the meeting is to be held in the Strange Masks House, one of the creations of architect Nakamura Seiji. From his own experience, Shishiya knows that each of Nakamura's houses becomes the scene of some grotesque murder, and hoping to confront the evil, Shishiya accepts Hyuuga's request. And as expected, the meeting at the Strange Masks House turns into a bloody tragedy, when the house is cut-off from the outside world due to a sudden snow storm in April, the master of the house is found murdered and decapitated in his room and masks have been put on, and locked on the faces of all the guests, including Shishiya, during their sleep (think The Man in the Iron Mask). With no way of escape or even seeing whom they are talking to, can the party make it out alive from Ayatsuji Yukito's Kimenkan no Satsujin ("The Strange Masks House Murder", 2012).
Kimenkan no Satsujin is the ninth novel in Ayatsuji's Yakata (mansion, house) series, which first started in 1987 with The Decagon House Murders (for a series overview, see this post). Shishiya had not acted in very prominent roles in the previous couple of volumes (from Kuronekokan no Satsujin on), but here he is back in the main role, in a rather classic format of the series, with him locked up together with some other people in one of Nakamura's devilish creations. The theme this time is masks, which is a motif for a lot of mystery fiction actually. "Everyone wears a mask, whether over their faces or over their hearts," one famous quote from the Ace Attorney series says and that's especially true in detectve stories, where practically everybody has something to hide, criminal or not. And how often have we not seen stories where people turned out not to be the persons they claimed to be? Sometimes, we have characters wearing actual masks, like the infamous Sukekiyo in Yokomizo Seishi's The Inugami Clan, who instantly attract all attention, and suspicion of those around them.
Ayatsuji brings this theme to the extreme in Kimenkan no Satsujin, as it's a rule inside the Strange Masks House for the host and guests to wear face-covering masks most of the time, and after the murder nobody is able to take of their masks anymore because they have all been locked. It's because of the actual masks that the reader will suddenly start to have suspicions about the identity of each of the characters, as you simply can't be sure anymore if the man in the mask is indeed who he claims to be. This plot device is used in interesting ways to work out several problems revolving around identity in mystery fiction, including obvious ones like suspicions about the identity of the decapitated victim and others. The face=identity theme comes back several times and I'd say that for the most part, this is done quite well: the problem of why everyone is made to wear their masks, as well as the reason for the decapitation work quite well in the context of the story.
Whereas Knox might lament the use of secret passages in detective stories, it's actually a vital element of the Yakata series: the series revolves around the houses designed by Nakamura Seiji, who loved weird gimmicks like secret hallways and hidden cabinets. Every time there is something resembling a locked room in the series, you can bet there's a secret hallway somewhere. But isn't that cheap, you might think? No, actually, it isn't. For one, it's always assumed that there is something going in Nakamura's creations and two, the existence of a secret hallway itself is not the mystery. They are always used as fair elements in the deduction process, so you have to look at these gimmicks in the light of questions as "who could have known about this secret hallway", or "who could have used this secret passage". In that respect, secret hallways are just as fair an element in mystery fiction as the bloody knife. Kimenkan no Satsujin too is bursting with secret gimmicks, but their use in the deduction process is completely fair.
I did find Kimenkan no Satsujin quite lacking in the 'wow' department. Up until now, all the books featured a big surprise twist, a trick that turned everything around and explained everything. For each book, I can explain in one sentence what the trick was. Kimenkan no Satsujin on the other hand feels more like it's a collection of smaller tricks that admittedly work together, but miss the big impact of earlier novels. Most of the mystery revolves around the decapitated corpse, issues of identity because of the masks and Nakamura's gimmicks mentioned above. True, there is one big twist at the end of the story that also ties in nicely with a very neat piece of misdirection, but it is not a plot device that can explain most of the mystery behind the novel, as featured in previous novels. Again, it's an element that ties in well with the face=identity thing, but it is not nearly as strong as that one thing from The Decagon House Murders or that what was pulled off in Tokeikan no Satsujin (people who have read those books probably instantly know what kind of twist I'm talking about). In comparison, the thing from Kimenkan no Satsujin? Oh, that, in combination with that other thing and don't forget this.
Overall, Kimenkan no Satsujin is a fairly solid entry in the series, with the more classical tone similar to earlier books in the series. For people who have been following the whole series, I think this one won't really disappoint. For people who haven't read the series yet; start somewhere else, because while fun, Kimenkan no Satsujin is nowhere being the best of the series and there are quite a lot of references to earlier books. The big question is however: what will happen next? Ayatsuji has said that he plans to end the series with the tenth volume, and while there is nothing like a grand narrative between the books (except for the focus on the protagonists and the houses created by Nakamura Seiji), I do suspect that the last volume will have something to connect all the books together more strongly and serve as a proper conclusion.
Original Japanese title(s): 綾辻行人 『奇面館の殺人』