Literature / Tantei Team KZ Jiken Note

aka: Genie Team G Jiken Note

KZ Detective Team.
Clockwise from upper left: Uesugi, Kozuka, Kuroki, Aya, and Wakatake

^{Click for the cover of The Missing Bike Knows} 

I'm Aya Tachibana. I couldn't have imagined that my encounter with four super-eccentric boys would change my life so much.

— Aya Tachibana, Opening Narration.

Aya Tachibana is a sixth-grader who frets and obsesses over friends, family, grades, and more. One day, she joins the "Tantei Team KZ" with four very idiosyncratic boys she met at Cram School. There is the glib and attention-grabbing leader Kazuomi Wakatake, the mysterious "expert of personal relationships" Takakazu Kuroki, the smart and stoic math genius Kazunori Uesugi, and the sweet-hearted Kazuhiko Kozuka who is good at social matters and science. Aya finds her place among them as the "language expert." "Tantei Team KZ" gets involved in modern-day cases, and even if they bicker from time to time, they collaborate by pooling each of their talents and skills to solve these cases.

Tantei Team KZ Jiken Note (The Case Notebook of KZ Detective Team) is a series of (35 as of March 2021) tween's mystery novels. It is a remake of Hitomi Fujimoto's 1992-1993 light novel KZ Shonen Shoujo Seminar by Ryou Sumitaki and illustrated by Komagata. The original novels were published by Kodansha since 2011 under the Aoitori Bunko imprint, targeting a upper-elementary audience. It received a animated adaptation by Signal.MD^note KZ is its first project. starting from October 2015, adopting 4 of the novels as 16 9-minute episodes and aired in NHK Education. It is being streamed by Crunchyroll in most parts of the world^list United States, Canada, Central and South America (including the Caribbean), South Africa, Australia, New Zealand, Europe, the Middle East and North Africa. It also currently has a manga adaptation by Megu Sakura, published in the anthology Nakayoshi.

Tantei Team KZ Jiken Note novels in release order

1. The Missing Bike Knows (March 2011, Adapted into Manga and Anime (episodes 1-4))
2. The Ripped Page Knows (April 2011)
3. The Keychain Knows (May 2011, Adapted into Manga)
4. The Egg Hamburg Steak Knows (November 2011, Adopted into Anime (episode 5-8))
5. The Green Cherry Blossom Knows (March 2012)
6. The Cinderella Express Knows^note First of a Two-parter (July 2012)
7. The Cinderella Castle Knows^note Second of a Two-parter (August 2012)
8. The Christmas Knows (November 2012)
9. The Backyard Knows (March 2013, Adopted into Anime (episode 9-12))
10. The First Love Knows, Wakatake's Chapter (July 2013)
11. The Angel Knows^note Chronologically between The Backyard Knows and The First Love Knows with some overlap (November 2013)
12. The Valentine Knows (December 2013, Adopted into Anime (episodes 13-16))
13. The Moth Fly Knows (March 2014)
14. The Princess Dress Knows (July 2014)
15. The Blue Diamond Knows (October 2014)
16. The Red Mask Knows (December 2014)
17. The Golden Rain Knows (March 2015)
18. The Tanabata-hime Knows (July 2015)
19. The Disappearing Bishoujo Knows (October 2015)
20. The Youkai Computer Knows (March 2016)
21. The Authentic Halloween Knows (July 2016)
22. The Idol Prince Knows (December 2016)
23. The School's Urban Legend Knows (March 2017)
24. The Dangerous Birthday Blues Knows (July 2017)
25. The Convenience Store Mask Knows (December 2017)
26. The Black Classroom Knows (March 2018)
27. The Library in Love Knows (July 2018)
28. The Disappeared Black Cat Knows (December 2018)
29. The School's Hidden Boss Knows (March 2019)
30. The White Witch at the School Gate Knows (July 2019)
31. The Cursed Love Story Knows (December 2019)
32. The Dangerous Best Friend Knows (March 2020)
33. The Dark Sick Room Knows (July 2020)
34. The First Love Knows, Sunahara's Chapter (December 2020)
35. The Calendar Vampire Knows (March 2021)
36. The Cinderella Staircase Knows (July 2021)
37. The Haunted Spot Knows (December 2021)
38. The Venus Helicopter Mom from Hell Knows (March 2022)
39. The Mumbling Soul Knows (July 2022)
40. Swooning for you: The Pink Heart Knows (March 2023)

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The series also has several spinoff series, and the three series are collectively called Jiken Note Series :

• Genie Team G Jiken Note (The Case Notebook of Genie Team G), which centers on Aya's younger sister Nako, set at four years after the beginning of KZ, when Aya is 16 and Nako is 11.
• KZ' Deep File, a more mature mystery novel series starring the boys of the KZ Detective Team, written by Hitomi Fujimoto.
• KZ' Upper File, novels in the same style as KZ' Deep File, but with the cast in high school.
• Justice will not Allow This!.^note Sore wa Seigi ga Yurusanai! This one, while still within the main KZ universe, has a tenuous connection with the main series: the main detective team in this series are three girls; one of them is Shinobu Nanaki's self-proclaimed suitor. Even then Shinobu isn't the most-featured Nanaki; the series focuses more on his uncle and cousins.

Genie Team G Jiken Note and KZ' Deep File novels in release order

Genie Team G Jiken Note:

1. The Christmas Cake Knows (November 2014)
2. The Star-shaped Cookie Knows (May 2015)
3. The May Donut Knows (May 2016)

KZ' Deep File

1. The Blue Pearl Knows (December 2015)
2. The Cherry Hill Holds a Crime (October 2016)
3. Someday, It Will Become a Legend (May 2017)
4. Dream of the Forest in the Fault (November 2017)

KZ' Upper File

1. Eve of the Paradise Lost (June 2018)
2. Hand that Opens the Closed Room (July 2019)
3. Mathematician's Summer (September 2020)

Justice will not Allow This!

1. The Disappearances on the Pearl Island (April 2022)
2. The Dreaded Dormitories and the Disappeared Club Members (May 2022)

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Tantei Team KZ Jiken Note contains examples of the following tropes:

• 10-Minute Retirement: The Moth Fly Knows have the KZ Detective Team briefly changed to KZ Social Service Team, and the five kids are already on the way to home visits to local elderly... only when their first client is not in house, while a men in his thirties said he went to hospital...
• A Day in the Limelight: For KZ, two examples so far.
  • The Angel Knows is set when Uesugi seeks treatment on his eyes in Switzerland. Thus the rest of the cast doesn't appear in this novel.
  • The Blue Diamond Knows is written in Kozuka's voice.
• Academic Athlete: Most of the boys in this series are members of KZ Soccer Team, chosen by Shumei Seminar to be a group of this. Much of the athlete part is already evident in the anime, but the first page of every novel reminded readers that the KZ team's minimum academic requirement is... to be at top 2.2% in nationwide testing^note The exact language used in the novels is the deviation value of 70; translated into statistics it is equivalent to two standard deviations above mean in a normal distribution.. The only exceptions are Sunahara, who was in the team but expelled due to conduct reasons, and Kozuka, who is never in the team in the first place.
• Adaptation Explanation Extrication: The anime turns each 200-plus-page novel into 4 9-minute shorts, so this is unpreventable. Using episode 1 as example:
  • In the anime the teacher never explained why the boys were in the Special Class. While in Uesugi and Kozuka's case one can immediately guess (lopsided grades), and in Wakatake's case the reason was given in Episode 3 (Highly fluctuating performance, which also earned his epithet "The Wave"), the reason Kuroki is there was never discussed. In the novels, the explanation is absenteeism.
  • When Aya introduces herself in front of the boys (and take a snipe on Wakatake), the way the Anime does it makes it difficult to understand why Kuroki calls her the "language expert" right after this. It is because the anime removed her yojijukugo dropping from the speech. The following is her speech, with the removed portion in italics.
  Aya: I'm Aya Tachibana. Reiseichinchaku^note calm and collected Uesugi-kun, onkoutokujitsu^note gentle, honest and earnest Kozuka-kun, happoubijin^note everybody's friend Kuroki-kun, and the snobby goganfuson^note arrogant Wakatake-kun, who can't even tell the difference between a human and a mailbox... It's nice to meet you all.
• Alpha Bitch: Naho Takeda, at least towards Aya.
• Alphabetical Theme Naming: The four KZ Detective Team boys have "Kazu" in their first names: Kazuomi Wakatake, Takakazu Kuroki, Kazunori Uesugi, Kazuhiko Kozuka. Broken as of The Disappearing Bishoujo Knows, when Tazuku Mikado joins.
• Alternate Character Reading: The first line of Aya Tachibana's Monologue puts it clear: "Write it as 'KZ', read it as 'Katsu'."
• Amateur Sleuth: The KZ Detective Team is essentially this, somehow of a modern-day The Hardy Boys.
• Age Lift: Made necessary because it's an adaptation of an old Light Novel series for a younger audience; the age of the cast was moved down for several years. As a side effect, sometimes the cast don't act like 12-year-olds; for example, in Tanabata-hime Knows, a 12-year old boy made a big marriage proposal to Aya through her parents, and the said parents do not object.
• The Beautiful Elite: The KZ soccer team are definitively considered as the "elite" in Shumei Seminar. While they occasionally have gonk members like Onozuka, most of the current or former members are quite handsome, to the point that the only non-member male in the case, Kozuka, looks a lot plainer than the rest.
• Because You Were Nice to Me: This is why Aya ignores KZ Detective Team and even her mother's warning against Sunahara; he shields her from verbal abuses at least once.
• Belligerent Sexual Tension: For those who ship, the relationship between Aya and Wakatake can be categorized as this. Wakatake is brash, impatient and Innocently Insensitive to the point that Aya decided to call him without any honorifics, but it's also the only pair where both have gone Green-eyed to each other—in The Egg Hamburg Steak Knows, Aya found herself in jealousy when she found Wakatake have been recently dumped, and in The Valentine Knows, Wakatake (together with the rest of the KZ Detective Team) are obviously jealous when they knew Aya is far closer to Sunahara than they think.
• Big Fancy House: Wakatake's large house is surrounded by olive trees, something Aya awed about when she first see it in episode 5. In particular it has a very large library, of which during Wakatake's father's absence Wakatake uses it as the meeting spot for KZ Detective Team.
• Blackmail Backfire: Of the "loss of leverage" type. In episode 16, as Sunahara stated he has evidence against the Japanese Delinquents group of scamming his foster family, leader Onozuka threatened to expose to the police all the laws the former broke under his orders. However, as it turns out, Sunahara is Crazy-Prepared enough to not break any law.
  Sunahara:Don't underestimate me. I only ever got close to you to gather evidence on you. All the money I said I stole for you were mine.
• Broken Pedestal:
  • Aya's first impression with Wakatake, Kuroki and Uesugi. Specifically, Wakatake crashing his bike on Aya, with Uesugi and Kuroki stopping by. First, Wakatake calls Aya a "moving mailbox." And then Kuroki greets Aya as if he is picking her up. Followed by Uesugi coldly commented Kuroki for "hitting on a girl again." Understandably, it's hardly a very good first impression for her. Although her opinions on the boys were rebuilt after spending more time with them.
  Aya: My admiration for KZ had just crumbled spectacularly.
  • In The Youkai Computer Knows, Nanaki's computer mentor pretty much made Nanaki's computer system her botnet. Nanaki was extreme distressed at this development.
• But Now I Must Go: Not after some act of heroism, but Sunahara pretty much uses this phrase at the end of The Valentine Knows after a romantic discussion with Aya over the starry sky. The reason for him to leave is he's a really bad victim of Not Evil, Just Misunderstood, and after having released from arrest twice without any charges, he believes he already gets a bad reputation as a Japanese Delinquent that he'd rather leave town.
• Cast Full of Pretty Boys: Downplayed. The KZ Detective Team is not exactly Bishōnen, but they are good-looking enough that western viewers often wonder the possibility a case of reverse harem. Being a series written for tweens, that is obviously unlikely. However, this is played the most straight in the G spinoff; the male cast◊ there is the most Bishōnen allowed in a Middle Grade Literature artwork.
• Character Development: As the series goes Aya seems to be knowing how she approached social skills wrongly.
• Chekhov's Gun: In episode 14, it reveals Wakatake's cell phone ringer sounds like a police siren. In episode 15, when The Team is in a stalemate with the Japanese Delinquents, Aya asks Kozuka to call Wakatake's cell phone, which breaks the stalemate.
• Chick Magnet: The Academic Athlete nature of KZ Soccer Team make their members to be this. Because of this, Aya's classmates were utterly jealous of Aya being friends with them. Even Shumei Seminar that organizes the soccer team realizes this; to avoid the problem of its members personally receiving a large amount of Chocolate of Romance over Valantine's, its members are not allowed to accept them personally while the fangirls have to put their chocolates into a collection box, with the recipient written on it.
• Chocolate of Romance: The Valentine Knows is partly around this, and this trope became several plot points.
  • Aya found she has nobody to give these to—Sunahara is distant, and she treats the rest of the Detective Team as Just Friends.
  • KZ Soccer Team's member are so popular with the girls that they're no longer allowed by their Cram School to accept those personally.
  • After knowing Sunahara being in a group of Japanese Delinquents, Wakatake came up with exploitation of this trope to check what's happening to the former—by having Aya sending him one of those, since no boys can resist it (the rest of the team agrees). The problem is Aya told them she would like to give this to Sunahara, so that's a really good chance...
  • Most of the drama of the story derives from the long journey for Aya to deliver her to Sunahara.
  • The ending of the arc actually makes the situation between the members of KZ Detective Team ambiguous—they made a chocolate cake at Wakatake's home on Valentine's Day, and share among each other. This can be interpreted from True Companions to Reverse Harem.
• Clear My Name: This is Wakatake's motivation for investigating The Backyard Knows; despite his cleaning of the school yard he is still reprimanded for not cleaning it, which he believes to be some other people dumping trash into the school overnight. He is right about this.
• Coca-Pepsi, Inc.: The third KZ'Deep File novel involves a MegaCorp called "Misumi," conveniently combining the real-life operations of Mitsubishi (in finance, heavy industries and paper) with the structure of Sumitomo (having a Blue Blooded patriarch that is widely respected, but holds little actual power).
• Cool House: In addition to what is detailed at Gadgeteer's House, Nanaki's house in The Youkai Computer Knows is egg-shaped, highly unusual in Japan where strict building codes mean most houses are modular.
• Comic-Book Time: At least 17 novels were written when the Detective Team are seventh graders.
• Continuity Nod:
  • Within KZ itself, the title of a previous novel is often raised when a later novel refers to something that the readers may not recall, for example:
  I first went to Wakatake's house during The Egg Hamburg Steak Knows''.
  Aya's Internal Monologue, Youkai Computer Knows
  • KZ and KZ'D are taken to be of the same universe; so plot points do cross-reference. Novel titles were no longer cited, however. For example, the opening lines of Cherry Hills Hold a Crime mentioned the fact that Uesugi had a brief drop in grades. This, of course, refers to The Backyard Knows.
• Corner of Woe: Wakatake has one of this (on top of his dad's swivel chair) at episode 8, due to losing the chance to publicly name and shame Sunahara Meats.
• Cram School: To put it this way, the cram school called Shumei Seminar is more central to this series than any other school, since KZ Detective Team goes to different schools in the day. This series also got into the cram school system a bit further than most works:
  • Shumei Seminar divides classes by academic performance, in a way similar to the actual practice in Japan. Aya got to know the KZ because she was sent to the "special class" in the cram school (on top of her current class) for being very lopsided; she's very strong in Japanese language but very poor in math.
  • The KZ Soccer Team is actually organized by Shumei Seminar.
  • The fact that students were kept until pretty late is also handled in the narrative, for example The Missing Bicycle Knows involves a convenience store robbery while sixth graders are still in cram school sessions.
• Crash-Into Hello: Subverted. Aya's first impression of Wakatake, Kuroki and Uesugi comes in this way. Specifically, Wakatake crashing his bike on Aya, with Uesugi and Kuroki stopping by. First, Wakatake calls Aya a "moving mailbox." And then Kuroki greets Aya as if he is picking her up. Followed by Uesugi coldly commented Kuroki for "hitting on a girl again." Understandably, it's hardly a very good first impression for her.
  Aya: My admiration for KZ had just crumbled spectacularly.
• Disabled Means Helpless: This is one way to explain Uesugi's behaviour in The Backyard Knows, animated as episodes 9-12. It's no longer possible to hide the fact that his vision has deteriorated to a point that he can no longer read standard print, something of a Dream-Crushing Handicap for a boy best known as a math whiz. What he does is attempting to leave his social circle quietly and without any explanation, so as to avoid invoking this trope—as a person who seems to be fixated in maintaining his face, he probably can't deal with sympathy well.
• Downer Ending: The The Egg Hamburg Steak Knows arc. Sunahara Meats can't escape from bankruptcy, and Sunahara himself leaves at the end of the arc. All after he declares to be Aya's fifth friend, something Aya, of course, happily accepts. The anime ends the arc with this:
  Aya, with a Longing Look: Hey, Sunahara, I'm proud of you. You're my fifth friend, after all. Forever and ever.
• Edible Theme Naming: The two novels in the G spinoff continues with the MacGuffin Title convention—and both MacGuffins in question are desserts.
• Edutainment Show: Being in a children's book imprint somehow enforces this trope, but the twentieth novel The Youkai Computer Knows takes one step further. That novel introduces a large number of computer science terms, ranging from the several flavours of C, to Deep Learning, and to D Do S.
• Elite School Means Elite Brain: Kuroki, Uesugi and Kozuka study in Kaisei Academy—which has been the top feeder school to Tokyo University for decades—and cemented their status as geniuses.
• Evil Counterpart: The "elite team" that "Phantom X" Onozuka attempts to recruit in The Valentine Knows is referred as the Japanese Delinquent version of KZ Detective Team in the novel. In the anime it's more nuanced, recall Onozuka is a former member of the KZ Soccer Team, while one of his recruits, Sunahara is one as well. Of course the bad news is Sunahara is only there for infiltration.
• Failure Is the Only Option: Wakatake never gets the attention he craves, even in the novels.
• Freshman Fears: one of the first problems Aya meets when she enters junior high is its social dynamics. She is appointed the Class Representative for some reason, but the local Alpha Bitch and her posse immediately ignores her, owing to a rumour about class appointees being the top student of the homeroom (which is Truth in Television in some Japanese schools). This is where Sunahara enters her life; he saves her by asking the class to keep quiet and invites her to start again. Aya's response? Because You Were Nice to Me.
• Friendship Moment: Several in the The Backyard Knows arc, in a way that made Aya somehow envious of "the boys' friendship."
• Gadgeteer's House: Nanaki's house as shown in The Youkai Computer Knows. He uses his skills to transform his house that he's forced to stay before majority into this. Specifically, it is pretty much managed by artificial intelligence, including driverless cars, robotic servants, and large numbers of sensors that reports literally everything in the house (to the point of enabling precision agriculture and horticulture). It's also self-sufficient in terms of food production, involving a fish farm and what the novel refers to as miniature farm animals.
• Genre Mashup: Tantei Team KZ Jiken Note is a combination of Detective Literature and a Middle Grade-level Romance Novel, with a bit of Reverse Harem mixed into the latter.
• Gray Rain of Depression: The latter half of episode 8, when the case of the month brings down Sunahara's father company, and he disappears from school.
• Heroic BSoD: Aya isn't good at handling pressure, but her Valentine's card to Sunahara being posted in the open in the part of The Valentine Knows animated as episode 15 just sent her to Troubled Fetal Position.
• Hey, You!: Ever since a point in episode 3 when Wakatake says "that's why I hate girls" to her face, Aya always calls without Japanese Honorifics.
  Aya's Inner Monologue: I'm not calling him Wakatake-kun anymore.
• Hidden Eyes:
  • In episode 12, Aya does this when she relays the Wham Line regarding Uesugi's situation to Kuroki and Kozuka.
  • In episode 15, Aya initially has those when she noticed her Valentine's note to Sunahara is posted to the train station's bulletin board, and people are seeing it as a serious Love Confession. Deteriorated to Troubled Fetal Position when she found it was Sunahara who posted it.
• Hoist by His Own Petard: The criminals in The Backyard Knows. Basically speaking: they steal some rare butterfly samples from the museum, wanting to sell to collectors. The problem is one of them is particularly poisonous.
• I Should Write a Book About This: This is all implied during the The Birthday Blues Knows novel that the series is Aya taking her senpai's advice of Write What You Know to heart. invoked
• Idiosyncratic Episode Naming: All novels, and by extension anime episode titles, are in the format of [MacGuffin related to the case] Knows.
• Initiation Ceremony: The humiliating type was used in The Valentine Knows (shown in episode 15). The test for entering Phantom X's "elite team" includes asking the person in question to perform embarrassing acts to prove their loyalty, which mainly involves running around the train station naked. In Sunahara's case, this involves asking him to post Aya's Valentine note to him in the train station.

• It's Not You, It's Me: Sunahara used that twice in The Valentine Knows in an attempt in distancing himself from Aya. Neither of them work, Aya's having a crush on him and was overly troubled by his apparent association with Japanese Delinquents.
• Joggers Find Death: Highly Downplayed in The Backyard Knows. Aya observed somebody dumping trash into Wakatake's school's yard from the outside, hence confirming Wakatake's complaint a day before.
• Just Friends: Despite how some viewers think about Aya's social life, she sees her relationships with KZ Detective Team as this, to the point of thinking they're not the people she's going to give Chocolate of Romance over Valentine's.
• Kid Detective: KZ Detective Team are middle-schooler Amateur Sleuths.
• Last-Name Basis: The four boys from the KZ Detective Team are usually referred to this way. Of course, with all the "Kazu"'s, it's rather confusing the other way round.
• Lethally Stupid: The driver in The Egg Hamburger Steak Knows started off doing Poke the Poodle just to let off steam, but then he switched to switching the meats in his truck, which ultimately caused the bankruptcy of his employer Sunahara Meat.
• Limited Wardrobe: It seems the cast only have at most three sets of clothing: school uniforms, the clothes depicted in the page image, and Soccer Team members also have their kit.
• Long-Distance Relationship: The Valentine Knows ends with the relation between Aya and Sunahara improved from Star-Crossed Lovers to this. It is more than clear that Aya and Sunahara love each other, and they have mutually confessed in this arc. However, Sunahara's brush with the Japanese Delinquents seriously bruised his reputation in town, so he declared But Now I Must Go. Although he promised to meet each other. Which of course appears in the novels, where he's Aya's classmate again in The Tanabata-hime Knows.
  Sunahara: Tachibaba... We can see each other, right?
  Aya: We can, right?
  Sunahara: (Looks at Aya's Chocolate of Romance) Yeah, I promise.
• Love Confession: By episode 15 Aya and Sunahara have quite clearly confessed to each other.
  • Aya's Valentine note to Sunahara is seen to be a "legitimate confession" by the people who read it at the train station:
  ''I want to believe in you. You have what it takes to find happiness. I give you these chocolates with all my heart. Don't forget I'm always rooting for you. Don't give up."
  • Sunahara said this when he calls Aya later that episode:
  Sunahara: But I was really happy. The chocolates and the card were your way of expressing your feelings, right? Right now, I...I like you so much, it's kind of embarrassing. I'm glad I met you.
• Love Dodecahedron: Even only from the anime, the more aged viewers can get this between Aya and the boys:
  • Aya and Sunahara are mutual lovers, with mutual Love Confession. However, they are hampered by Long-Distance Relationship.
  • Aya may seem to hate Wakatake, but the dynamics between the two smells of Belligerent Sexual Tension, including mutual Green-Eyed Epiphany.
  • There are signs of Aya having a crush on Kuroki at different points, sometimes seeing him the boy of her dreams (episode 2), but since Kuroki is a natural charmer, he may or may not be interested in a relationship with her.
  • Uesugi possibly has a crush on Aya, but he has a problem on Cannot Spit It Out, so Aya doesn't even know this of the fact.
• MacGuffin Title: Most of the books are named [Object related to the case] Knows.
• The Mentor: Wakatake and Uesugi teaches G's cast on amateur sleuthing.
• Minor Crime Reveals Major Plot: Aya discussed this trope with Kuroki during The Backyard Knows, expressing some disappointment that the crime involved in the arc was indeed minor, performed by a perennial small-time criminal without more apparent complexities. But the story does go that way, although still downplayed: it lead to a case of museum theft which causes the loss of some expensive butterfly specimens.
• Mood Whiplash: Often invoked.
  • In episode 2, Aya refuses Wakatake's request to write a notice for a lost bicycle because she thinks Wakatake is being snobby and Wakatake's bicycle has nothing to do with her anyway. Then Wakatake apologizes, saying he makes the request because he thought she is "one of us," and went downstairs. Aya then realized she may have been losing potential friends for being Innocently Insensitive, as Wakatake treated her as a friend but not vice versa, and Wakatake's the first person who called her a friend. So she chased downstairs, only for her to realize Wakatake wasn't known for egging people on for nothing:
  Wakatake: Do you feel like writing the statement now?
  • In The Valentine Knows, Sunahara twice invoked It's Not You, It's Me to try to distance himself from Aya. In both cases, those lines are right after words that confess his "likeness" to her.
• On One Condition: In The Youkai Computer Knows, Nanaki is supposed to inherit the family fortune at 20, on the condition that he doesn't leave his house before that point. He doesn't mind this arrangement, but Aya, recalling her Friendless Background, finds this appalling. Rendered completely moot at the end of that novel, due to the bankruptcy of the family.
• Once Done, Never Forgotten: Sunahara's arrest for assault (which is a big case of Cassandra Truth in its own; the person he attacked was trying to burst his father's car's tires) severely affected his reputation so that he was expelled from the soccer team and everyone sees him as a Japanese Delinquent.
• O.O.C. Is Serious Business: Played straight in episode 9 when everybody else's being gravely concerned with Uesugi's well-being after (1)Dropping off Top 50 in math when he usually gets the first place, (2) skips both Cram School and the Detective Team's proposed investigation, and (3) for an Academic Athlete, the impossible feat of slipping off the staircase. Kuroki has to skip the case because of it, possible to handle Uesugi's problem. Of course. His vision has deteriorated to a point that a complete loss of vision is not impossible.
• Opening Narration:
  • From The Ripped Page Knows on, the first chapter (titled Aya Tachibana's Monologue from The Keychain Knows on) of every novel would include a summary of what KZ Soccer Team is, followed by a recap of what is essentially the first few minutes of anime, then followed by some different materials. The exceptions are The Angel Knows and The Blue Diamond Knows, as they are written in Uesugi and Kozuka's voice respectively. And then since the 21st novel, the title of this chapter drops any pretense and just calls it To all first-time readers, but the text has not changed significantly (other than adding a bit about Nanaki of course).
  • The Anime version uses the following:
  I'm Aya Tachibana. I couldn't have imagined that my encounter with four super-eccentric boys would change my life so much. This is the story of the exciting cases that we, KZ Detective Team, solve.
  • The corresponding chapter in G is called The Ditzy Character.
• Poke the Poodle: The driver behind The Egg Burger Knows tend to do this to let off steam, such as blowing up the boss' tires. Turns to Lethally Stupid when he started to spike the beef with pork.
• Product Displacement: The novels doesn't mind talking about the absolute top schools in Tokyo. Kuroki, Uesugi and Kozuka went into Kaisei Academy, one of the most prestigious schools in Japan, and Mikado mentioned University of Tsukuba High School at Komaba, which on par with Kaisei. These names are displaced in the manga and the anime adaptations. Despite Wakatake and Aya's schools are fictional in the first place, they were anonymized as well.
  • In the anime Kaisei only referred to as "the elite private school." Wakatake and Aya's schools were not named.
  • In the manga, Aya's own school is now named Kodan, after the publisher Kodansha, and Kaisei is only referred as "the academically strongest school in Japan."
• Puppy Love:
  • In episode 13, second-grader Nako said she's going to give Chocolate of Romance to a male classmate over Valantine's.
  • As for the main recurring cast, despite most of them still cast their relationships in friendship terms, it's the kind of friendship where Green-Eyed Monster can occasionally occur. (See Ship Tease, below)
• Quantity vs. Quality: This trope was discussed by Uesugi in episode 13. As the cast heads home, Wakatake asks Aya how he can get as many Chocolates of Romance as possible, and he made it clear he doesn't care whether he likes the girl in question, nor whether the chocolates were given out of courtesy, as long as he gets tons of it. Uesugi then facepalms, saying Wakatake probably can't help it, since "guys have a 'quantity over quality' vector."
• Quivering Eyes: Aya had them several times.
  • In episode 7, when she learns that Sunahara's father's company will be punished for one of the staff's Tampering with Food and Drink. The fact that the punishment involves that company's bankruptcy hasn't even raised yet.
  • In episode 11, when she learns from Uesugi the reason behind the latter's strange behavior during the arc: his eye are so bad that he can't even see text anymore. And a moment later, both the speaker and the listener gets this, as Uesugi mentions any treatment has at most 40% success rate, and bears the real risk of a complete loss of vision. And then when she relayed this information (with Hidden Eyes) to Kuroki and Kozuka in episode 12, they both get this!
  • In episode 13, Aya has this when the Detective Team tells her Sunahara is among the group of delinquents that has been harassing Cram School students.
• Reverse Harem: While downplayed due to this being a series about and primarily aimed at tweens, there's no escaping the fact that it's one girl surrounded by boys that she and everyone around her consider to be cool and good-looking, and she even develops some feelings towards some of them. While not as strong as older RH series, it still has the same effect.
• Science Foils: The KZ Detective Team is formed by a group of lopsided students. Two of them particularly fit in this mold: Uesugi, the Stoic Spectacles mathematician, and Kozuka, the Boy Next Door biologist. In addition, Aya, the Nervous Wreck linguist and Nanaki, The Shut-In computer scientist, also adds to this trope.
• Second Episode Introduction: Second Scene Introduction to be exact. Most of the cast has been introduced in the first chapter when they Crash-Into Hello, but Kozuka is only introduced at the Special Class classroom.
• Self-Imposed Exile: Sunahara goes into this after the twelfth novel The Valentine Knows. His several brushes with Japanese Delinquents makes everyone in town to believe he is one himself, which causes him to decide to leave the town.
• The Series Has Left Reality: the series is purely realistic for most of the time—it's an edutainment series for tweens, after all. However, Nanaki, introduced in the twentieth novel, claims he has the ability to see spirits; and since then there have been paranormal subplots for subsequent novels—but the main plot maintains realistic.
• Sesquipedalian Loquaciousness: Invoked in The Missing Bike Knows. When Aya introduces herself in front of the boys of the Special Class (and take a swipe on Wakatake), she decided to show off her strength in Japanese language that the teacher mentioned moments earlier. She does it by dropping yojijukugo, four-kanji idioms of Chinese origin, that accurately describes the four boys.
  Aya: I'm Aya Tachibana. Reiseichinchaku^note calm and collected Uesugi-kun, onkoutokujitsu^note gentle, honest and earnest Kozuka-kun, happoubijin^note everybody's friend Kuroki-kun, and goganfuson^note arrogant Wakatake-kun, who can't even tell the difference between a human and a mailbox... It's nice to meet you all.
• Ship Tease: One really can't blame older viewers from seeing a harem forming around Aya. Even talking about the 4 (of 19) arcs that have been animated, Aya has been ship-teased with all boys with the exception of Kozuka.
  • In episode 2, when Kuroki walks Aya home, Aya having Imagine Spot on what kind of man she imagines.
  • In episode 5, Aya being jealous about Wakatake dating somebody at school (and dumped), despite supposed to be hating him.
  • In episode 11, Uesugi's calling Aya "angel."
  • In episode 13, Uesugi tells Aya that while guys usually are "quantity over quality" regarding Chocolate of Romance, he is not—while blushing.
  • In episode 14, all four boys from KZ Detective Team gets jealous when Aya says she doesn't mind giving Chocolate of Romance to Sunahara.
  • Also in episode 14, Sunahara gives the following of a response when Aya calls her and wants to give him the aforementioned Chocolate of Romance:
  Sunahara: I lost my breath for a moment when I heard your name. And when you mentioned Valentine's Day, I kind of stopped breathing entirely. Do you have an idea how happy this makes me?
• Shown Their Work:
  • The First Love Knows discusses the equipment of a meth lab accurately (beakers, electric heaters, red phosphorus, lots of ventilation), to the point of mentioned it's prepared through pseudoephedrine from cold medicine—of course, far short of providing tweens a meth recipe.
• Shōjo Demographic: As Middle Grade Literature it is only marketed by its age group—10-12—without discussion of gender. Yet its manga adaptation is published in Nakayoshi, a shoujo anthology, hence putting the series into this demographic.
• The Show of the Books: The anime, being adapted from a series of Middle Grade Literature.
• Sibling Yin-Yang: Aya and her sister Nako. Aya is introverted, constant worrying, and detail-oriented, while Nako is energetic, carefree and ditzy.
• Simultaneous Arcs: During The Backyard Knows, Uesugi leaves for Switzerland to treat his deteriorating eyesight, and come back during The First Love Knows, Wakatake's Chapter. The Angel Knows is about what happened to Uesugi during his time there; and the author actually notes this novel is chronologically simultaneous to Backyard and First Love.
• Spice Up the Subtitles: Despite being a family-friendly anime, the Crunchyroll subs have the characters swear on some lines.
• Spinoff:
  • Genie Team G Jiken Note, a series focused on Aya's little sister Nako, after a 3-year Time Skip.
  • KZ Deep Files, a mystery novel series written for older audiences, written by Hitomi Fujimoto.
• Spiritual Successor: Originally intended to be a tweens' rewrite of KZ Shonen Shoujo Seminar.
• Star-Crossed Lovers: The Egg Hamburg Steak Knows ends with a downplayed version. Sunahara's family business closed as a result of the case, and he disappeared from school. What Aya gets is his phone number. And that's right after he declared to be Aya's "fifth friend."
• Stock Shoujo Bullying Tactics: In episode 5, Aya as Class Representative was plainly ignored when she makes an announcement. Sunahara saved her by asking the class to keep quiet and invited her to start again, which brought forth her Because You Were Nice to Me despite his reputation.

• Tampering with Food and Drink: The Egg Hamburg Steak Knows arc involves this, as in how pork get into the supposedly pure-beef patties that Wakatake happened to have eaten, causing some allergic reactions. It was done by a Lethally Stupid driver of the meat processor, who spiked some of the beef shipped to the plant with pork in spite.
• Team Title: Partly so.
• Teen Genius: While the academic requirements for the KZ Soccer Team potentially puts most of the male cast in the main series as this, Uesugi and Kozuka plays this trope the straightest.
• Troubled Fetal Position: In the part of The Valentine Knows animated in episode 15, Aya does this after finding her Valentine card to Sunahara being posted on the train station's notice board, and overhearing that it was Sunahara who posted it.
• Two-Teacher School: Aya supposedly has two attend two class—Class B and the Special Class. However, the anime only shows Egawa, her instructor in Class B.
• Unnecessary Roughness: Onozuka, a leader of Japanese Delinquents in The Valentine Knows, was a member of KZ Soccer Team half a decade prior to Present Day. He was infamous for this, and was forced out of the team as a result.
• Wall Pin of Love: In the twentieth novel The Youkai Computer Knows, Aya was given this by one of her classmates (which is not part of her recurring cast, mind you). The plot relevant point is that Mikado noticed the smell of synthetic cannabinoids that rubbed off from him to Aya.
• Wham Line: In the anime, expect the third episode of every arc to contain at least one of them. However, among those the straightest example would be the one in Episode 11 (The Backyard Knows, Part 3). Up to this point, while the rest of the cast have been concerned about Uesugi's recent performance drop and withdrawal from their activities, they assume it as a problem of time management. Only when he comes to Aya's house to say farewell he incidentally blurbs out the real reason for his own behavior.
  Uesugi: I can't see.
• Write What You Know: Discussed In-Universe. In The Birthday Blues Knows, Aya's senpai at the Literature club recommends her doing this to start creative writing. It is all implied that this series is Aya following this advice to heart.
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