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 Bishōnen 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.
Berserk Button: Kumiko and her fellow teachers don't like it when someone takes a crack at their students.
Tsuruta doesn't like to fight people weaker than him, but insult his appearance and all bets are off.
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.
Bishōnen: Shin. Normally, this would have every female character lusting after him, but Kumiko scarcely notices and Fujiyama has her own peculiar tastes.
Book Dumb: Most of the students had no choice but to attend Shirokin for this reason.
Didn't See That Coming: The Chairman of the school wanted Kumiko gone. When he learns her true heritage, he contacts the head of the Alumni association and the head of the Parents' group for the school. Turns out the alumni met her when she dressed as a guy to make sure whatever tests he was putting her students through for a job application, they were safe, and so he respected her for that. And the parent called in is the boss of a friend of Kumiko's family and she helped his son become less of a jerkass, and so is thankful to her. Though they didn't know the whole truth about her situation until the Chairman told them, they believe the Chairman is on their side and they all sign a pledge to not speak a word of this to anyone. Ever.
Double Standard: Rape, 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.
Later in the manga, a few younger guys take a liking to Shin, but keep quiet about it.
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.
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 and they do not collect protection money to extort them, they actually do protect them.
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.
Oddly Small Organization: Kumiko's Yakuza Family. A new gang member noticed this and thought this meant they were easy pickings. The leader of said group knew that despite being small each member was pretty much a One-Man Army and the leader has the influential power to pretty much summon every yakuza member to his side at a moment's notice.
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
Pointy-Haired Boss: The leader of the Nekomata-kumi. His underlings wonder why they even work for him, and when Kudou's plan to kidnap Kumiko falls through and Kuroda invades the Nekomata headquarters, the leader is the only one who didn't get to escape because he had knocked himself out with his backscratcher.
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.
One Steve Limit: Subverted during the Okinawa trip. Uchi's gone missing after a fight with some local toughs, and while searching for him, Yamaguchi and Sawada overhear some local bikers mention that Uchi's been kidnapped. Cue lots of running and fighting before it becomes clear that it's a different Uchi...
Odagiri from the second season comes closest to returning the favour by stopping someone from taking a whack to Yankumi's back with a metal pipe in the movie.
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, which means 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".
Also in the movie, of all the places trainee teacher Odagiri could have gone actually assigned to, he ends up at Akadou where Yankumi is! Subverted in the end as the Principal reveals he had asked to be assigned to Akadou, knowing he would meet Yankumi there again. Which means the earlier scene where he is surprised to see Yankumi, Baba and the Principal is actually an act!
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...
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.
Five-Man Band: The main students in each season easily fit into this.
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: There's one in every season but Odagiri Ryu from Gokusen 2 is the standout example. He also picks up this role in the movie.
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, 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.