Week 11: 笑わない数学者 - Mathematical Goodbye (S&M Vol.3) [END]

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笑わない数学者 - Mathematical Goodbye (S&M Vol.3) Home Thread

Week 11


Start Date: Mar 5th
Previous Part: Week 10


Week Start Date Chapter Page Count
Week 11 Mar 5th Chapter 11 ~23

Discussion Rules

  • Please use spoiler tags for major events in the current chapter(s) and any content in future chapters.
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Proper Noun Readings

Previous Proper Nouns
Name Reading Notes Proof
犀川 創平 さいかわ そうへい (Week 1)
西之園 萌絵 にしのその もえ
片山 和樹 かたやま かずき Moe’s classmate
天王寺 翔蔵 てんのうじ しょうぞう Professor, grandfather of 片山 和樹
西之園 恭輔 にしのその きょうすけ Moe’s deceased father
湯川 ゆかわ Architecture researcher
天王寺 律子 てんのうじ りつこ Wife of 天王寺 宗太郎; actress
天王寺 俊一 てんのうじ しゅんいち Son of 天王寺 宗太郎 and 律子; genius mathematician; actor
鈴木 昇 すずき のぼる Driver; his mother works for the professor
天王寺 宗太郎 てんのうじ そうたろう Professor’s eldest son; mathematician; famous author; deceased
片山 亮子 かたやま りょうこ Professor’s daughter; 和樹’s mother; 俊一’s aunt; widow; relationship with 湯川
片山 基生 かたやま きせい 亮子’s deceased husband; 和樹’s father; architect who designed the remodelling of 三ッ星館; died of cancer
鈴木 君枝 すずき きみえ Professor’s housemaid
片山 志保 かたやま しほ 和樹’s older sister
諏訪野 すわの Moe’s butler
鈴木 彰 すずき あきら 昇’s father (Week 4)
萩原 はぎわら Police officer investigating the case on-premise

Sooooo… can someone please explain the ending to me >_< Who was really the professor? What’s the last scene about? Does it take place after the events, in which case it sounds like the (real?) professor is not dead, or is it a flashback?

Found this interesting article. It’s pretty clear that the real professor is the skeleton that Moe found, because of the book title (the 「博士が笑う声が聞こえた」line is quite clever, wish I’d noticed it myself!). However, I’m not so convinced about the identity of the other two 老人. This article has the “professor” as Kisei and the guy in the park as Soutarou, but this other article has them swapped, so who knows. I’m also confused about why they all look so old even though they should be a generation apart, and 亮子 doesn’t sound like she’s that old.

It also features a quote from the author: 「トリックは簡単で、誰でも気づくものです。意図的に簡単にしたのです。」Well there goes my confidence :pensive:

Edit: this one is also interesting, although it doesn’t give concrete answers. But it posits that the reverse trick (Mori says there’s a 逆トリック) is that the roles of the reader and the 名探偵 (Saikawa) are swapped. Indeed, we notice the statue trick before Saikawa does, and we have access to the hint from the book title, which Saikawa doesn’t.


I do have some thoughts but my notes are a mess :caught_durtling: I’ll try again next week!


To expand a bit on that part if you don’t wanna read the article (and if it wasn’t very clear) : there are 3 “people” whose identity is not very clear: the person we’ve been assuming was the professor, the old dude in the last scene, and the skeleton Moe found. Which one is the real professor? The book title is 笑わない数学者, so the professor is the one who doesn’t laugh. The dude in the park at the end is clearly smiling/laughing, and when Saikawa leaves the professor’s office for the last time he hears him laughing 「博士が笑う声が聞こえた」Therefore the professor can only be the skeleton.


So… how is that going for you? :slight_smile:


Hi! :durtle_hello: Sorry for making you wait, I wanted to reread parts of the book to “fact check” some stuff, but haven’t had the time to do so. But I figure I could just post the thoughts I had, anyway.

Hidden due to length of spoilery stuffs

So we have four characters whose whereabouts are a bit of a mystery: the professor 天王寺 翔蔵 (ca. 80 years old), the author 天王寺 宗太郎, the architect 片山 基生, and Noboru’s father 鈴木 彰.

My theory is that Akira was the one who died in the car accident 12 years ago, not Soutarou. I think we’re probably all on the same page on that one, right? So when Kimie told Saikawa that she received a phone call and the manuscript from Akira, that must have been a lie. I think it was Soutarou himself who sent that manuscript after having finished writing. (Though one might wonder why the writing style didn’t resemble his usual writing style… :thinking: )

He supposedly stayed with the professor in the basement for at least four years while writing that manuscript, I think? And then killed himself, but from the hint about the title and stuff, we know that the skeleton has to be the real professor. Maybe he died by natural causes, either way Noboru and the “professor” carried him out to the woods to hide the body. Was this while Noboru was still in middle school or maybe a bit later? From the visit at the hospital we know that while he was in middle school, Noboru heard from the “professor” that he was his real dad. Maybe that was Soutarou who pretended to be the professor. Could also have been Katayama Kisei if my theory is wrong.

In chapter 4, part 6:
The fact that Saikawa watched Katayama Kazuki and Suzuki Noboru playing billiards and thought, “huh, they look very similar in appearance”. So maybe they have the same father? :eyes: Katayama Kisei?

Even if it doesn’t work out timeline-wise, maybe Kimie and Soutarou (who seemed to love each other) were secretly together even back then. She was angry at Ritsuko for being Soutarou’s wife and also angry at Ryouko when she found out Soutarou actually liked Ryouko too.

While Noboru was still in middle school, he heard directly from the “professor” that the professor was in fact his real father. I don’t think he never heard Kimie talk about it. And I don’t know if this makes sense (I’ve kinda forgotten the timeline), but maybe the professor had already been “switched out” by the time Noboru learned that fact during middle school.


Thanks for writing this down! I’ve already forgotten a bit of the details, and I’m fuzzy on the timeline. But it kinda makes sense to me that the “professor” would actually be Soutarou which would also be Noboru’s real dad. Which means the guy in the park is Kisei. I’m still confused on how they manage to swap people who are supposed to be a generation apart.


Yeah, that puzzled me a bit too, but then again, I often find it difficult to tell the age of a Japanese person, so maybe it’s the same for Japanese as well :woman_shrugging: :rofl:

Joking aside, it might also be a factor that the person in the basement lived a pretty secluded life as it seems, and if the person was out of sight for like 10 years and then somebody else (who looked similar anyways, I guess) claimed to be that person, then who would be able to object to that…

Anyways, @Redglare thanks for adding some fresh thoughts to the puzzle! We will of course never find out but I think it’s pretty amazing how many theories and plot twists we were able to generate from this book. I just hope the next one can live up to the hype… :wink:


Just finished reading this (just discovered this reading groups, and just happened to be reading 笑わない数学者 at the time…) and I planned on lurking until Vol. 4 started up, but decided to throw my two cents into the ring after reading the other posts.

Thanks to miwuc for finding all those interesting blog posts about the ending.

WARNING: Spoilers for Perfect Insider すべてがFになる

Regarding “why couldn’t people tell them apart if they were a generation apart”… Wasn’t confusing people a generation apart a major part of Perfect Insider as well? Maybe that’s just a thing in the Mori-verse :joy:

On a more serious note, like NicoleRauch suggested, the fact that he was living isolated from everyone else could definitely factor into it. If they had been living normally it might have been impossible, but since it could have been weeks or even months between the last time they saw Shouzou and the first time they saw Soutarou/Kisei. And once they get the switch off, as everyone else interacts with Soutarou/Kisei more, that becomes their image of “Shouzou” in their minds.

Also, Soutarou had a neurotic breakdown and Kisei had cancer, and those things could have also caused them to end up looking much older than they really were.

(Back to spoilers just for this book)

I think the idea that Soutarou or Kisei could’ve been Noboru’s father is really interesting (as if the family tree in this book didn’t shift enough). The professor just told Noboru that he’s his father, but… we don’t know who the professor is. Both Soutarou and Kisei had reason to want Ritsuko dead (Soutarou just hated Ritsuko, and Ritsuko is the one who drove Kisei’s twin brother to a mental breakdown), which gives the motive a bit more oomph than for Shouzou imo. I think Kazuki and Noboru’s resemblance could be taken as evidence that Noboru is Soutarou/Kisei’s son rather than Shouzou’s but, since Soutarou and Kisei are identical twins, I don’t think it can be taken as proof that he’s more likely to be Kisei’s son than Soutarou’s.

However, the big issue with this idea, imo, is Kimie. I think the timeline is ambiguous enough that Soutarou/Kisei could’ve been Noboru’s father and told Noboru that after swapping with Shouzou, but since Noboru was born 19 years ago, way before any of the ridiculousness started, Kimie needs to know Noboru’s father for a fact. And I don’t think Mori would pack so much into this mystery of the professor’s identity if there was a third party who could just easily and definitively answer it.
(Ofc, it’s possible that Soutarou/Kisei is Noboru’s father and Kimie is unaware of the swap… but that’d mean Kimie “lied” when she said the professor was Noboru’s father, and that just seems to far-fetched with all the other stuff going on.)

One last possibility is that Shouzou was Noboru’s father, but it was Kisei/Soutarou who told Noboru that.

…Thinking back on it all again, the fact that Noboru was born blind suggests to me that Shouzou really was his father, since children of older fathers are more likely to have birth issues.

That ended up being more than I expected. See everyone at vol 4!


Good point! I’d forgotten that the same trick was used in すべてがFになる. But at least I remember it being explained somewhat. In this book the issue is not even mentioned. To be fair, the character swap itself is only vaguely brought up at the end so I guess we’re supposed to figure it out ourselves.

Welcome to the book clubs!


Very interesting points, I totally forgot about that parallel. And for Kimie, one can never be sure whom she was referring to when she said „the professor“. Also, she lied before, so I‘d totally expect her to lie again regarding Noboru‘s father and all that. :woman_shrugging:

Looking forward to reading vol. 4 with you!


You and me both :smiley: Well, at least now I know why all the characters never seemed to notice the statue trick…

The article is interesting! Especially with the old man = laughing ≠ the professor style formulas.
Also the parallel of the man in the basement always talking about the architectural concepts of inside/outside is a cool detail.

I also agree with Mori’s assessment that this book is the most suited for less hardcore mystery/crime fans. Reading along and making up your own theories is a lot of fun, but it becomes impossible when the murders and tricks and motives become too absurd :sweat_smile: This one had about the right level of brainfuck to it.
I think I’m fine with staying at the “I read this book and I enjoyed it” level, without checking back and thinking back on all the possible connections. So many people and interpersonal relationships! So I don’t really have any final thoughts :slight_smile: (I actually thought that the final scene was a flashback to Moe’s childhood, so I didn’t connect the dots there at all…)

I enjoyed reading everyone’s final thoughts though! (and generally reading through all the threads)
If I manage to catch up to vol 4 I’ll hopefully be able to take part in the live discussion, instead of always commenting half a year after the fact :yum:


And that’s another S&M book finished! I think I enjoyed this one the most so far, though I think the second book had some more gripping “I can’t stop reading until I find out what happens” bits.

I must admit to getting a bit lost with all of the who might be who and is related to who complex family tree so it was really helpful to read everyone else’s theories! I’m not sure I have a definitive guess for the identity of the 博士 etc, and I kind of quite like that. A little mystery to be left with. I really enjoyed the final 博士 and 犀川 conversation. The person that records the audiobook did a really good job at filling it with tension and making the 博士 kind of intimidating/scary in a way.

Got a few things next in my reading list but I don’t think it will be long until I come back to this series for vol 4! :female_detective::man_detective: