Few before Asuka Higuchi's beloved mother Kazue died, she told her daughter to search for her place in the world and look for her long-lost father. Problem is, she didn't leave almost any leads behind! All Asuka knows is that his surname is "Sudou" and that he's in Tokyo, so Asuka grabs her few belongings and her motorcycle and goes all the way from Hokkaido to the capital, firmly determined to find her dad.
On her journey, Asuka sees a guy around her age being rough to a younger girl, and to stop their fight she hits the boy with her bike. It turns out, however, that the boy is the girl's older brother and was merely trying to bring her back home. So she drives them there.. and they make a rather awkward discovery: they are Manato and Kazusa Sudou, her half-siblings! The story doesn't end there, however: the siblings's mother died long ago, and they've never properly met their dad. He is said to be the chairman of a local school and provides for the two Sudous, but is completely hands off otherwise and therefore Manato has pretty much raised Kazusa on his own.
Not really knowing what else to do, Asuka decides to move in as their "Neesan" and stay around at least until the mysterious Mr. Sudou shows up. Things get pretty tricky, however, since Kazusa really cannot accept Asuka's presence, Manato isn't really convinced either at first, Asuka must get used to this new life... and for worse, Manato and Asuka start feeling attracted to each other!
Released in 1990, Shinshunki Miman Okotowari ("No pre-teens allowed" or "Forbidden to pre-teenagers") is one of Yuu Watase's earliest mangas. It had a sequel (Zoku Shinshunki Miman Okotowari, from 1993) and a special chapter (Shinshunki Miman Okotowari Kanketsuhen, from 2000).
The original Shinshuki Miman Okotowari has the following tropes!:
- Accidental Pervert: One of the series's running gags is having Manato see Asuka in one or another stage of undress...
- All of the Other Reindeer: Asuka grew up in a small Hokkaido town, where the kids bullied and ostracized her for being an illegitimate child.
- Alpha Bitch: Come ON, Youko!
- Badass Biker: Asuka, oh yeah
- Brother–Sister Incest: Asuka falls for her half-brother Manato early on in the story, and he eventually comes to reciprocate. And then they learn that they aren't blood-related after all - Kazusa is Asuka's little sister, and Manato was just adopted by the man who turned out to be Asuka and Kazusa's actual dad.
- Clingy Jealous Girl: Both Youko and Kazusa.
- Cool Big Sis: Asuka appointed herself as Manato and Kazusa's "Oneechan" aka big sister so she'd find a way to be accepted by them.
- Disappeared Dad: Asuka's biggest goal is to get the mysterious "Mr. Sudou" to meet up with her and aknowledge her as his daughter.
- Dynamic Entry: How the audience meets Youko. The one on the receiving end is Manato, much to his displeasure and Kazusa's anger.
- Japanese Delinquents: Asuka used to be one of these, until her mother Kazue fell fatally ill.
- Japanese School Club: The gymnastic club turns out to be very plot-important, since Asuka wants to join it so it'll help her reach her dream to be a PE teacher and will help her meet her unseen dad.
- Large Ham: In the third chapter, Youko managed to: glomp the Hell out of Manato, have a Cat Fight with Kazusa literally over him, SCREAM once she meets Asuka face to face declare herself as Asuka's rival and leave while letting out a Noblewoman's Laugh. All of this, in her very introduction.
- Love Dodecahedron: Asuka likes Manato. Manato likes her back. Kazusa has a HUGE case of Big Brother Attraction. Asuka's rival and local Student Council President Youko likes Manato. Manato's friend Tooru has a crush on Kazusa at first and she may have liked him a little, but then moved on and fell for Asuka, who also kinda liked him...
- Love Triangle: Kazue Higuchi was involved in one of these in the past. With the men that would be the fathers of Manato, Kazusa and Asuka.
- Missing Mom: The series started few after the death of Asuka's beloved mother.
- Not What It Looks Like: How Asuka meets the Sudou siblings.
- Only Six Faces: Are these Asuka, Manato, Kazusa, Youko and Tooru... or Miaka, Tamahome, Yui, Nuriko and Tasuki?
- The Ojou: Youko, with traits of both the Ice Queen and the Spoiled Brat types.
- Passionate Sports Girl: Asuka is a very good gym practitioner, and so's her rival Youko
- Plucky Girl: Asuka isn't prone to give up soon.
- Promotion to Parent: Manato has practically raised Kazusa since their early years.
- Sailor Fuku: Asuka and Manato's school has seifuku for the girls and gakuran for the guys.
- Shoujo: Among Watase's first ones, too.
- The Rival: Youko, for Asuka
- Unskilled, but Strong: Asuka has borderline Super-Strength and lots of stamina, but she lacks the proper training to be a gym practitioner at first. i.e, when she tries to use the uneven bars to raise to Youko's challenge and enter the team, she begins spinning in them... and then she has such a strong momentum that she simply CAN'T stop. Even when she eventually has to let go and Manato pulls a Diving Save to catch her, Youko realises her potential and lets her into the club, if only to keep her as her rival.
The sequel Zoku Shinshunki Miman Okotowari has the following tropes:
- A Day in the Limelight: The second chapter is dedicated to Kazusa, and the third to Youko.
- A Man Is Always Eager: GODDAMMIT, MANATO! It goes dangerously into Attempted Rape during the Class Trip to Hokkaido, and it almost destroys his and Asuka's relationship.
- Beautiful All Along: Sonoda, Youko's butler, was always drawn with rather... odd features. But when he comforts Youko after the Epic Fail of her "boyfriend quest", his actual face is clearly seen and he's gorgeous.
- Beta Couple: Kazusa and Tooru, eventually.
- Can't Hold His Liquor: Manato, and how.
- Doppelgänger Replacement Love Interest: Defied, arguably deconstructed. Kazusa dates a boy named Takanari, who is Manato's Identical Stranger save for his glasses... yet not only it doesn't work out, but she eventually concludes that she missed out on many prospect boyfriends because of her Big Brother Attraction.
- Josei: It touches some more adult themes than the original.
- Looking for Love in All the Wrong Places: Youko's quest in her chapter is to find herself a good boyfriend. This being Youko, Hilarity Ensues.
- My God, What Have I Done?: Manato, when Asuka fends him off in the Attempted Rape incident.
- My Girl Is Not a Slut: Subverted. Manato refuses Asuka when she directly offers herself to him and says "this Asuka disgusts me", but it turns out he is still feeling guilty over the Attempted Rape incident.
- Snow Means Love: Asuka walks on Manato speaking to Kazue's snow-covered grave and apologizing very heartily for what he almost did to her daughter. She forgives him and they tearfully hug in the snow.
- Their First Time: A whole chapter is dedicated to Asuka and Manato trying to get it on. They almost do, buuuuut...