Rouge Noir is a short jousei manga by Kyouko Mizutani, spanning two volumes.
When Ayane Tezuka was 19, she was a cute college student aiming to be a piano player. In these days she also was the private tutor of a young rich boy, Kou Narumiya, and sparks simply flew between them! However, not only Kou was from one of the richest families in Japan but he was only 14, despite being much Younger Than They Look. Once Kou's mother noticed and harshly warned Ayane to not get too close to Kou, such an attraction ended up in... well, not good terms.
Flashforward to six years. 25-year-old Ayane is now a beautiful school teacher in an all-girls school, is about to marry her long-time boyfriend and fellow teacher Naoto Murakami and her life seems to be placid and perfect... but she hasn't really forgotten Kou. All of a sudden, while attending a jazz-piano audition, she finds the now older Kou again. Old feelings sort-of return, and Ayane's heart is a mess from then on...
Rouge Noir has the following examples:
- Alpha Bitch - Bitch in Sheep's Clothing: Rena Morikawa, the star of the school chorus that Ayane directs. Not only she falsely accuses Kou of trying to rape her (which is ironic, considering what he did do years ago), but she also leaks info about him and Ayane to the Headmaster of the school out of spite.
- Chekhov's Gun: Ayane once plays the piano for Kou while tutoring him. Kou later plays the same piano song in the Evans club's opening
- Chekhov's Gunman: Sorta: two of Ayane's coworkers, Shibasaki and Okamura, are featured in another short story from Mizutani.
- Don't You Dare Pity Me!: Ayane, when she leans that Kou din't take up the jazz-piano job because of her.
- Elegant Classical Musician: Both Kou and Ayane, in different degrees. Both are talented pianists, and Ayane is also a pretty decent singer.
- Expository Hairstyle Change: Ayane used to have long hair at age 19. At age 25 she has a much shorter cut. By the end of the series, as she and Kou manage to go the Earn Your Happy Ending way, Ayane has let it grow long again, as a sign that her emotional damage is more or less healing.
- Green-Eyed Monster: What made Kou snap on Ayane and rape her was seeing her with Naoto after he had called her to his cell in the middle of a BIG Heroic BSoD and she didn't reply. (Because Naoto had found her cellphone and deleted his messages).
- Grey Rain of Depression: When Ayane breaks up with Naoto, she does it via a cell call under the rain.
- Heroic BSoD: Ayane, after Kou rapes her. Kou has one of his own immediately afterwards, when she's gone and what he did to her fully sinks in.
- Hot for Student: Played with. When Ayane was Kou's tutor, there was UST between them but nothing came out of it. Or so it seemed. Six years later, when they meet again, he still calls her "sensei".
- Rena and Naoto are also sort-of involved. It's... weird. And when he decides to go to Hawaii in the end, Rena follows him suit.
- Hot Teacher: Ayane and her boyfriend Naoto. Kou later becomes a student teacher in their workplace, and that's how they "officially" find each other.
- Just a Kid: Kou has big problems with that, to the point of a Berserk Button. He ends up pretty much raping Ayane and giving her a "The Reason You Suck" Speech when he believes she's reinforcing the trope on him (on top of having had a huge fight with his parents and being horribly depressed over that, but Ayane won't know such things until much later).
- Modesty Bedsheet: Ayane, as she goes downstairs after she and Kou have (consensual) sex.
- Near-Rape Experience: When Ayane goes to Kou's house after he's (falsely) accused of trying to rape Rena, he pins her to the bed. When Ayane tells him the same words she told him before he raped her years ago and admit that she's jealous of Rena, Kou stops himself and lets her go.
- Rescue Romance: Kou helps Ayane when she's harrassed by a drunkard.
- Scarpia Ultimatum: Sorta. Naoto knows Kou didn't try to rape Rena, but he blackmails Ayane with it: he'll only testify in Kou's favor if she accepts to marry him. He later backs off and testifies anyway.
- Sensei-chan: "Ayane-cchi", though not as much as others. She's also the extremely rare example where the Sensei-chan is the lead.
- Shower of Angst: Ayane, after being raped by Kou.
- Tomboyish Name: Ryuunosuke is actually a girl puppy.
- Unwitting Instigator of Doom: Had Naoto not picked up Ayane's cellphone and deleted Kou's messages for her due to outta jealousy, Kou wouldn't have horribly exploded on her the way he did.
- What the Hell, Hero?: Kou towards Rena, when she tells him she ratted him and Ayane out."What a pitiful woman! Are you only capable of finding happiness through the misfortune of others?!"
- Wounded Gazelle Gambit: Kou is falsely accused of trying to rape a girl named Rena Morikawa. It turns out that, in the end, it was this: Rena wanted to "help" Naoto to "clean up competition" and take Kou "out" so he'd have the way cleared to win Ayane's affections. It doesn't really work anyway, since Naoto sees that Ayane was more feisty than he thought.