Gokusen

University graduate Yamaguchi Kumiko's first teaching assignment is at Shirokin High School, an all-boys school renowned for being full of delinquents. She is put in charge of the worst class in the school -- class 2-D. Fortunately, teaching and helping delinquents has always been her dream, and as she is heiress to a Yakuza group, she is more than equipped enough to handle any trouble a bunch of snot-nosed kids can cause.

Schools aren't tolerant of gangs and people of dangerous backgrounds, so Kumiko's relationship to her yakuza family must remain a secret. Unfortunately for her, there is one extremely smart and disgruntled Bishonen in her class full of idiots, Sawada Shin. He sees through her very poor cover-up and realizes that she is an Action Girl. His demands for a fight are mocked by Kumiko, after which Shin's respect and passing interest only grows.

Throughout the rest of the series, Kumiko wins over her originally mistrustful students and improves their lives for the better. Shin quickly learns of her Yakuza background, ends up on friendly terms with her family, and is neck-deep in gang-related troubles over and over again. Kumiko remains oblivious to his feelings towards her while she focuses her own attentions on yakuza lawyer Shinohara, even though many others in the series have noticed Shin's feelings and are actively trying to help him.

Gokusen is fairly similar to Great Teacher Onizuka in premise -- become trustworthy to the delinquents and teach them lessons through "Tough Love". However, Kumiko is properly educated and her secret background plays a large part in the series -- for example, her students think she is in debt to yakuza because of one of her poor cover-up excuses, and she brings in a rather conspicuously shady fellow when she suddenly needs to tutor her students in boxing.

The manga was serialized in YOU, a Josei magazine, and while it does have many Shonen elements it is noticeably geared more towards females and fanservice is kept to a minimum though there are some notable exceptions. The anime adaptation has been licensed for release in North America and can be found in retail outlets with larger anime sections. The multiple seasons of the live-action television drama, however, remains locked behind the language barrier.

Tropes used in Gokusen include:

Action Girl: Kumiko was trained to fight by her uncles and is very effective at it
Badass Teacher: Kumiko; Fujiyama is also very protective in her own way, though she's no Action Girl like Kumiko
Bad Bad Acting: Kumiko and her Yakuza family couldn't act their way out of a wet paper bag, the only reason she can fool most of her students is that they range from simple to the borderline retarded.
Best Her to Bed Her: Kumiko pulls this trope to get out of an attempted arranged marriage. However her tactics only make the prospective groom fall more in love with her and determined to win the fight and her hand.
Big Fancy House: Shin's residence
Bishonen: Shin. Normally, this would have every female character lusting after him, but Kumiko scarcely notices and Fujiyama has her own peculiar tastes
Distaff Counterpart: As stated above, Kumiko is the Distaff Counterpart to Eikichi Onizuka. Only difference,Onizuka was a delinquent while Kumiko is the Ojou to a tough as nails Yakuza clan.
Even the Guys Want Him: Believe it or not, Kumiko's grandfather was described as this in his youth.
Evil Teacher: Miura, at first, although he's undergone some character development.
The Glasses Come Off: Whenever Kumiko switches from her demure teacher persona to her yakuza one. It shows in her speech, too: her "civilian" self speaks formally in a cutesy voice, but when she gets mad she suddenly starts growling in coarse, macho Japanese.
Gonk: So many that you can actually tell which characters are genuinely attractive, rather than leaving it up to Informed Attractiveness.
Hot for Student / Hot for Teacher: Besides the Shin and Kumiko hijinks, Miura-sensei's obsession with Shin, and, arguably, Fujiyama-sensei, as she always jokes about which of the cute boys she would sleep with.
Ho Yay: The manga can probably get away with stuff like this because the characters involved are gonks.
- Or this, though less extreme.
Large Ham: All the Kurodas except Kumiko's grandfather.
Love Can Make You Gonk: Kumiko does this whenever she is fawning over Shinohara. Her eyes go from their usual fixed glare to big, sparkly, bishojo-standard and can flick back and forth between panels when the situation calls for it.
Love Triangle: Shin -> Kumiko -> Shinohara. Manga Canon points to Shin and Kumiko getting together
Manly Tears: Frequently indulged in by the men of Kuroda.
Neighbourhood Friendly Gangsters: The Kurodas engage in illegal activity but nothing appears to be all that immoral or cruel. To the point the neighborhood actually really like them.
Nerd Glasses: Kumiko's glasses are actually arguably multipurpose, and are sometimes used as Mask Power or Scary Shiny Glasses.
Norio Wakamoto: Voices Kuroda second-in-command Ooshima in the anime
Obfuscating Stupidity:
- Kumiko's ditz-acting seems to work on almost everyone in the series, even though she always slips into "yakuza mode". She passes this off as being a big fan of yakuza movies and TV shows.
- The school principal is this as well because beneath his erratic, and occasionally perverted actions, he is revealed to be an intelligent man who cares for his students and wants what is best for them.
Oblivious to Love: Kumiko puts so much of herself into her work and helping her students that she doesn't notice Shin's feelings towards her at all. It takes her a moment to process his confession to her and is floored when it turns out Everyone Can See It.
The Ojou: Kumiko's yakuza family often calls her Ojou.
Only Sane Man: Shin, Shinohara, Ryuuchirou, and mostly Yankumi. Mostly.
Overprotective Dad: the Kurodas kept scaring off our heroine's boyfriends when she was younger
Rape Is Ok When It Is Female On Male: Early in the manga, Tetsu and Minoru see Kumiko mooning over Shinohara-sensei. Wanting to help, they offer to hold him down so she can rape him, but Kumiko just smacks them.
Scary Shiny Glasses: Miura-sensei
Secret Identity: Kumiko tries to keep her Yakuza background secret at work, although eventually everyone knows. It turns out that it was the reason the school director hired her, figuring she'd be tough enough for the job.
Sitting on the Roof: A large amount of scenes take place on the roof of the school.
The Stoic: Shin very rarely changes his expression of casual disinterest for anything or anyone.
Talking Animal: Fuji, but only to Shin in comic-interlude episodes of the manga
Ten Minutes in the Closet: Shin's friends lock him and Kumiko together in a storage room to encourage intimacy.
Yakuza: Kumiko's family.

The Live Action Adaptation provides examples of:

Adaptational Attractiveness: No two students are not Bishonen.
Aesop Amnesia: It takes a little while for the students to become savvy to the fact that Yankumi's not going to look down on them or mistrust them out of hand.
Big Damn Heroes: Yankumi. Sometimes the True Companions attempt it, but they often get thumped for their trouble.
Bishie Sparkle: In the second series, Kujo-sensei from the girls' school across the road.
Catch Phrase: The head teacher frequently demands to know whether Yankumi is "doing something unnecessary". Yankumi calls her students daiji na seito my precious students.
Colourful Theme Naming: The high school of the first series is named Shirokin or "white gold" as in the manga, but the second series' school is Kurogin "black silver" and the third's school is Akadou or "red bronze".
Cool Old Guy: Kuroda Ryuuichiro.
Cut Lex Luthor a Check: Whoever in class 3-D is responsible for the impressive graffiti could probably make a decent living off of his/their art skills.
Dawson Casting: Avoided. High school seniors 17-18 are played by actors aged 18-22.
The Glasses Come Off: Kumiko always unties her pigtails along with removing her glasses before a fight.
Hot-Blooded: Yankumi.
Lighter and Softer: Yankumi, her family, and her students have all had their edges filed off. In fact, the whole Yakuza element seems to have been swept under the rug entirely. On the other hand...
- Family-Unfriendly Violence : Serious beatdowns are given to high school students almost Once an Episode, with little recourse to the Battle Discretion Shot. On the third hand...
- Hollywood Healing : Students limp home from said beatings with a little cosmetic blood and a sympathy-grabbing wince when in real life they would probably have broken bones, concussions, internal bruising, etc.
Once an Episode: Or near to it. Yankumi's students get beaten up by guys who are nastier than they are, then those guys get beaten up by someone who is nastier than they are: Yankumi. Also, Yankumi consults with her grandfather for advice on what to do over copious amounts of sake.
Only Sane Man: The second season's Odagiri Ryu.
Recurring Riff: A distinctive piece plays when Yankumi performs her signature hair-band-and-glasses-removal preparation to start beating on some thugs.
Sorting Algorithm of Badass : Yankumi can face down her crop of high school badasses because, as inclined as they are to fighting and getting in trouble, she was raised by the yakuza and delinquents are just small fry compared to her folks back home. Most of the threats Yankumi faces are somewhere in between her own rank on the scale and that of her students.
Stealth Hi Bye: Yankumi pulls off a Stealth Hi at least once an episode. Shin and the others occasionally get in on the act.
Suspiciously Similar Substitute: Each season begins with Yankumi going in to teach at class 3-D of a new school, which is filled with bishounen delinquents who she inevitably wins over, helping them with their troubles over the course of the season, culminating in their graduation. Each season also features new love interest for Yankumi, with the old ones disappearing without a trace except Baba in seasons 2 and 3. Seasons 2 and 3 also have Yankumi being fired from a different teaching job for teaching her students yakuza phrases, before going to that season's class 3-D. Each class also seems to feature one student who acts as the Only Sane Man and has father issues and an implied crush on Yankumi (Shin in Season 1, Ryu in Season 2, and Yamato in Season 3).
This Is Something He's Got to Do Himself: Second-season's Takeda challenges a college-level boxer to a fight over a girl and gets the tar kicked out of him. Yankumi and her friends don't intervene, even though Takeda is getting wiped out and thrown down on sharp, pointy rocks.
True Companions: In the second season, Yabuki, Odagiri, Tsuchiya, and Takeda are rarely seen without each other, and when they are it usually means something bad is going down.
Wide-Eyed Idealist: Strangely, Yankumi.