硝子の塔の殺人 🗼 (ABC) Week 9

[Akashelia]

硝子の塔の殺人 Week 9

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Week 9	October 25th, 2025
Chapter(s) and sections	最終日: 2, 3
Start page	396
End page	425
Page count	30
Previous week	week 8
Next week	week 10

Vocabulary

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Character names (p.6)

Full Name	Occupation	Room
神津島太郎こうづしまたろう	館の主人	壱の部屋
加々見剛かがみつよし	刑事	弐の部屋
酒泉大樹さかいずみたいき	料理人	参の部屋
一条遊馬いちじょうゆうま	医者	肆の部屋
碧月夜あおいつきよ	名探偵	伍の部屋
巴円香ともえもどか	マイド	陸の部屋
夢読水晶ゆめよみすいしょう	霊能力者	漆の部屋
九流間行進くるまこうしん	小説家	捌の部屋
左京公介さきょうこうすけ	編集者	玖の部屋
老田真三おいたしんぞう	執事	拾の部屋

Illustrations before the prologue

Participation

Will you be reading along with us this week?

Will you be reading with us?

• I’m reading along
• I will catch up later
• I’m still reading the book but I haven’t reached this part yet
• I’ve read this previously but I’m here for the discussion
• I’m reading this book after the club has finished
• I’m no longer reading the book

• Votes are public.

[downtimes]

Okay, penultimate week. Second challenge unlocked. I wrote down many notes again, even though this week’s reading was pretty short. Did you pre-read the book to choose good week end points, by the way?

I mostly liked what happened this week. It started strong with him going down by 月夜s hand. I liked that part. You could totally read between the lines that she already knew.

So our speculation that there is something in the empty space between the rooms was right. It was pretty obvious. I’m not sure if I’m a massive fan of this reveal, though. The author even acknowledges that 密室 mystery shouldn’t have a “haha, there was another way in” solution. But as far as I understand it, it wasn’t used for the murders. It’s just that there is another layer to the whole thing we don’t understand yet.

I was really on board with 遊馬 getting some more space to shine, solving the 踊り人形 felt okay, since it had to do with DNA/Amino acids, and he is a doctor after all. I could follow that part. On the other hand, that he solved the whole second layer of the mystery apparently on his own feels a little too much/undeserved.

I’m still baffled why the 踊り人形 do exist at all, who would benefit from the group finding it and getting access to the second staircase?
We still have the layer of 神津島 wanting to reveal a mystery that shakes the foundation of mystery novels left? Maybe he tried to set up some mystery for them to solve during their stay in the tower, and that part was related to finding the second staircase?

Also, who left all the necessary items to solve the 踊り人形 in the 展望室? It has to have been 円香 or 老田 if they are the only ones who know about the staircase. On the other hand, 月夜 had all her books from the bookshelf in her room in disarray. Maybe she found something and knows about it too?

That brings us to the staircase.
It’s not connected to the 地下牢 as far as I understood. That’s why it might really have been 神津島s plan for them to find it. It was also not exactly revealed if you can enter from each of the rooms. As far as I understand it, there is no keypad in the 本棚 itself. You can only open it from the staircase?
遊馬 went in from the room, but only after opening the door from the staircase.
The only entrances would then be in the 発電室 and 展望室.

Also, who could logically be in the staircase on the first night after his murder? I can only think of 神津島 but he was clearly fighting the puffer fish poison?

All that is to say. I don’t have a solid theory what the second challenge’s solution might be. But I’m looking forward to theories of others. I’ll probably continue reading right away, since the last week is pretty long. Therefore, I might not comment much.

Btw, has somebody read “Think of a number?” it sounds like an interesting book. Maybe I’ll introduce some English literature into my reading.

[snowwater]

Initial thoughts

I really enjoyed this week - it was short, but I couldn’t keep the book down. Solving the 踊り人形 really hyped me up, as someone working in this field, I enjoyed how it was related to the DNA and amino acids (I don’t think I’d ever have guessed, though) and it felt like an elegant way to connect it to Trident and 神津島’s research.

@downtimes

I’m still baffled why the 踊り人形 do exist at all, who would benefit from the group finding it and getting access to the second staircase?

@downtimes

Also, who left all the necessary items to solve the 踊り人形 in the 展望室?

It really feels like someone set 遊馬 up to be able to solve this mystery and find the staircase. Perhaps someone who knew he was the murderer since the beginning (the person within the staircase that saw him kill 神津島 in the first night?) and who would need to have planned that he would ultimately be locked in the 展望室. I am actually starting to doubt if 月夜 is really the mastermind behind it all - if yes, that would mean that she knew, since the beginning, that 遊馬 was (one of) the murderer and yet she humored him by having him play the role of Watson… on one hand, that could be true (I’m especially suspicious of who pushed him down the stairs and 月夜 “nursing him” afterward) but I feel there’s an additional layer missing.

@downtimes

Also, who could logically be in the staircase on the first night after his murder? I can only think of 神津島 but he was clearly fighting the puffer fish poison?

I feel like there is something we are missing in regards to his murder, illustrated by the fact that 遊馬 went to double check if he was indeed dead (and that confirmed whichever realization he had). Perhaps 神津島 actually died slightly later then 遊馬 thought? Or something else ultimately contributed to his death?

I can see that 遊馬 will take that gun and confront the others in the next part… I wonder if he is slowly starting to lose his mind, too?

[Malinkal]

Summary

@downtimes

I’m still baffled why the 踊り人形 do exist at all, who would benefit from the group finding it and getting access to the second staircase?
We still have the layer of 神津島 wanting to reveal a mystery that shakes the foundation of mystery novels left? Maybe he tried to set up some mystery for them to solve during their stay in the tower, and that part was related to finding the second staircase?

Also, who left all the necessary items to solve the 踊り人形 in the 展望室? It has to have been 円香 or 老田 if they are the only ones who know about the staircase. On the other hand, 月夜 had all her books from the bookshelf in her room in disarray. Maybe she found something and knows about it too?

It’s surely got to be the same person who set it all up, for 遊馬’s benefit, I’d assume
I’m leaning massively towards 月夜

@snowwater

I am actually starting to doubt if 月夜 is really the mastermind behind it all - if yes, that would mean that she knew, since the beginning, that 遊馬 was (one of) the murderer and yet she humored him by having him play the role of Watson

That seems like more evidence to me that it’s her. Someone going to all the trouble to set up riddles specifically for 遊馬 seemingly, knowing he’s the “murderer”, would then be more likely to keep him close and show him a certain set of events. It feels like it’s 月夜 behind it all leading 遊馬 towards a certain direction, to me

@snowwater

I feel like there is something we are missing in regards to his murder, illustrated by the fact that 遊馬 went to double check if he was indeed dead (and that confirmed whichever realization he had). Perhaps 神津島 actually died slightly later then 遊馬 thought? Or something else ultimately contributed to his death?

It specified that 神津島’s shoulder and arm were very stiff and hit the ground hard, so I guess Rigor mortis? I don’t know much about it at all but Wikipedia先生 shows this image about the timeline

(warning, bit of a gruesome picture, dead bodies)

Summary

If his corpse is still stiff from Rigor Mortis, maybe that means he died later, and thus it wasn’t 遊馬 who killed him. There was something about a stun gun… or maybe something else, but I’m not sure how it fits together

Separately there was also the blood on the staircase. Maybe it’s from 巴’s corpse being moved differently to the window drop? Or maybe it’s the 真犯人 who injured themselves somehow.

I don’t have the patience to go and work it all out completely, but I’m pretty confident that whatever the secret reality is, 月夜 is probably behind it. She seems like the perfect fit for being obsessed with mysteries, seemingly knowing what is going on all the time (and more than she lets on), and the incredibly suspicious staircase bit with 遊馬 earlier on. Plus she seems like the exact person who would set up 遊馬 with a specific set of clues leading him to the conclusion which he reached, because she knows him by far the best and has spent the most time with him. I’ll be very surprised if it’s anyone else, but I’m sure there’s stuff to be uncovered about other people too. No idea about motive or how exactly it all fits though.

Not sure about the 神津島 mystery reveal bit - earlier on I thought it was all planned by him to happen after his death, but now I’m not so sure. He might have been alive later than thought, but I don’t think he set everything up. No idea what the mystery there could be

[Akashelia]

@downtimes

Did you pre-read the book to choose good week end points, by the way?

Not at all! Entirely decided because of the length of the chapters. Happy it fits so well

Replies and own comments on week 9

@downtimes

On the other hand, that he solved the whole second layer of the mystery apparently on his own feels a little too much/undeserved.

He did spend the first 5 hours of captivity doing nothing before waking up though

@downtimes

I’m still baffled why the 踊り人形 do exist at all, who would benefit from the group finding it and getting access to the second staircase?

There’s someone trying to guide 遊馬, since the glass tower model was left on top of the book needed to decipher the message. So the message was also left in advance for him. Now who was it again who led him to go investigate 神津島’s corpse again? And whose suggestion was it to look him in the collection room? Hmm…

@downtimes

On the other hand, 月夜 had all her books from the bookshelf in her room in disarray.

Really? Didn’t notice or forgot that, interesting.

@downtimes

I can only think of 神津島 but he was clearly fighting the puffer fish poison?

I think he was faking it. 加々見 died faster. 神津島 had time to draw a letter with chocolate and everything. I think that’s what 遊馬 realizes in the end, the corpse is not as rigid as it should be after 4 days.

@Malinkal not quoting you, I’ve read your comment last, but looks like we agree on pretty much everything xD you even prove the point of rigor mortis nicely

My own thoughts:
I thought it was weird in the first chapter of this week’s assignment that 月夜 was revealing the solution of another murder, without having everyone gathered like last time. Especially having a 1 on 1 with the killer and telling them they are the killer sounds like a very bad idea. Made a lot of sense, that the other guests were behind the door listening (though would have been fun to know, what she had told them before to bring them there).

Loved the second chapter! 遊馬 woke up and remembered all the unanswered questions. When he realized because of 神津島’s connection to DNA that there was another stair, I also realized that the code was going to be with A,C,T,G, 4 symbols and groups of three! But then he did the deciphering work for me, thanks 遊馬. Probably wouldn’t have been able to go anywhere with THINK OF A NUMBER anyway.
Fun that they ended up using a book from 2010, I wonder if the author has heard about that and what he would think of it. It does sound like an interesting book.
Also wow must be satisfying to use the same password everywhere and it just works.

Things are unraveling again but they feel more true this time.
For me, it’s definitely 月夜. She had an alibi for both crimes but never talked about it, she took a shower after 巴’s murder I believe, she could make 遊馬 do whatever she wanted. I think there are still more things we don’t know, but I’m convinced she’s hiding a lot of things.
I think 神津島 wanted to stage a mystery and make his big announcement after that, but then maybe 加々見 made a mess by actually killing people. 月夜 cleaned up and now she runs away with a new book.
It also makes for a pretty good happy ending, if 神津島 was killed by someone else, then good-guy-遊馬 hasn’t killed anyone after all.
Looking forward to next week

[downtimes]

I already read a good chunk of next week. But what I write here is not a spoiler. Fun to look back on this week’s responses

@Akashelia

I think he was faking it. 加々見 died faster

加々見 did eat all the rest of the pills in the case, compared to 神津島 who only ate one. I would expect a bigger dose of the poison to work more intensely/faster.

@Akashelia

Also wow must be satisfying to use the same password everywhere and it just works.

We are all human. I know so many people who do exactly that. I, for one, switched to a password manager and everything is unique now

[Akashelia]

@downtimes

I, for one, switched to a password manager and everything is unique now

Proud of you I tried to raise that issue at my workplace after seeing all my colleagues saving their passwords in clear in a word doc or excel or notepad, people looked at me strangely…

[lifev]

First, thoughts before I read others comments.

I liked that Yuuma did not try to kill Tsukiyo, I would be very much disappointed. He took the reveal pretty well and he deserves a pat on his shoulder for that. And finally after the pressure is gone, his brain started to work, and he solved the dancing men riddle! Bravo!

I have no idea what would happen next. Maybe I need to reread the first murder to understand or something. Here are some joke theories:

• Koudzushima is not dead, in the room it is a doll, and he enjoyed what was happening during these 4 days hiding in the other rooms/the secret stairwell.
• Nobody else from the guests is a mastermind. It is us as readers who are looking at the drama happening here and Yuuma found the proof in the dead body somehow from the hidden stairwell. And the book we are reading is the one mentioned by Koudzushima in the beginning. We pushed Yuuma from the stairs because he was acting stupid. And now, when he is on the hidden stairwell, he is actually in the real world and can haunt us for reading the book and judging him.

After reading other comments, I have nothing to add. I’m not sure what theory to build. But it was fun to read them! Although I feel like Tsukiyo can be the one who staged the rest of the mysteries, it feels a bit too simple.

[simias]

The author loves to use こめかみ and I keep forgetting when it means so I looked up the etymology to see if it would help and I think it will:

[simias]

omg omg

I really liked this week. I’m more on board for this than the weird closed room mysteries.

I think island guy is behind it and left the clues. I think this mainly because of a meta-narrative standpoint (fitting for this book): the big reveal teased at the beginning has to factor into all of that. Also if island guy didn’t die, 遊馬 is not a murderer and we get a happy ending for our protagonist.

I think the body in room 1 may be the person who was in the empty cell? Maybe island guy did weird surgery/genetic stuff to make them look like him so that the others wouldn’t realize that he wasn’t dead? Who else could have been using the staircase, I don’t think anybody else was unaccounted for when everybody rushed to the last floor.

What’s strange is that 遊馬 seems to assume that the truth is so shocking that he’ll need a shotgun to convince the others, so I feel that it goes beyond a simple switcharoo.

I dismissed the second staircase theory before because that feels too easy, but I guess that it didn’t really play a role in the first part of the mystery so I’ll allow it.

[Akashelia]

If you’ve made it so far, time to read until the end of the book! Or if you’ve already finished it, time to comment!

硝子の塔の殺人 (ABC) Week 10

硝子の塔の殺人 Week 10 Advanced Book Club Home Thread [image] Week 10 November 1st, 2025 Chapter(s) and sections 最終日: 4, 5, エピローグ Start page 426 End page 498 Page count 73 Previous week week 9 Next week (not yet) Vocabulary Prebuilt JPDB deck: Glass no Tou no Satsujin – Prebuilt decks – jpdb Discussion Guidelines Spoiler Courtesy Please follow these rules to avoid inadvertent ネタバレ. If you’re unsure whether something should have a spoiler tag, err on the side o…