Tokyo’s prestigious Hachimitsu Private Academy is a girls’ high school boasting top-tier education and disciplined students. Or at least it was a girls’ school. With the implementation of new policies, the academy sees the enrollment of Kiyoshi, Gakuto, Shingo, Andre and Jo, five boys who experience a girl to boy ratio within the school of a whopping two hundred to one. Contrary to their sweetest fantasies, none of the boys are actually capable of talking to the girls. Craving some sort of female interaction, the boys decide to take up a very dangerous task: peeping into the girls’ bath. With their plan thwarted by the infamous Underground Student Council, they are sentenced to a month into the school’s prison run by the USC, where they experience harsh treatment---treatment which will see them broken and their friendship rigorously tested.

Prison School is a show that deals heavy doses of humour through hyperbole – highly exaggerated situations, ecchi scenes, and ridiculous ideas drive the plot while the characters get up to insane yet very serious shenanigans which give the anime unexpected suspense from time to time. Prison School’s reliance on ecchi makes it very similar to Okusama ga Seitokaicho and the theme of the intrusion on a character’s regular school life is prevalent in both shows: one show’s main character finding out that he’s married, the others are thrown into an on-site school prison. Also, due to the setting of both shows being in high school, the existence of a school regulatory body such as the Student Council as an entity bearing much power in definition and within the very plot of these shows. Did we mention that it’s ecchi?

16-year-old Yuuki Rito has had a huge crush on his classmate Sairenji Haruna for a very long time and plans on one day confessing his feelings for her, but Lala Satalin Deviluke, a princess of the Planet Deviluke, one day appears in Rito’s bathtub. Fleeing a politically motivated marriage on her home planet, Lala suggests that she and Rito should marry. Thus begins Rito’s life of harbouring an extra-terrestrial princess and all the crazy and lewd adventures that one such life brings.

To LoveRu is a colourful romantic comedy in which the protagonist Rito finds himself in quite the predicament with the prospect of marriage is presented to him due to unforeseen circumstances, much like Okusama ga Seitokaichou. Where ecchi is concerned, the anime makes use of an extensive and vibrant harem featuring many beautiful girls of different personalities with whom Rito interacts and finds himself in many compromising, comical and somewhat sexy situations. If you enjoy interplanetary high school marriages, ecchi and outrageous adventures To Love-Ru is To Love YOU. Did we mention that it’s ecchi?

Japan has implemented a bill which sees all forms of obscenity public or private banned by law, upheld by the distribution of special collars, used to monitor citizens and maintain Japan’s high public morality. Okuma Tanukichi, son of an infamous terrorist who opposed society’s new restrictive laws, decides to enter a school most decorated for its high public morality and joins its Student Council in order to get closer to his crush, Nishikinomiya Anna, the Student Council President. However, on the way to school on his first day, he runs into the infamous Blue Snow, a terrorist who spreads lewd material to the general public. In order to recruit him to her terrorist organisation, SOX, Blue Snow reveals herself to be none other than Student Council Vice President Kajou Ayame, who seeks to use Tanukichi’s knowledge of sexual matters to help her and SOX distribute sexual propaganda and educate the chaste and ignorant society created by the chastity law.

Much like in Okusama ga Seitokaicho, we see the central role played by the Student Council in Shimoneta, as the object of the protagonist’s affiliation. More than that, the student council president in both Shimoneta and Okusama begin to bear romantic feelings for the protagonist. The SOX organisation’s quest for sexual liberation also bears a striking resemblance to Wakana Ui’s campaign speech in which she promised thorough sex-ed. The protagonists of both anime bear a similar studious and driven personality, Izumi showing his ambition through his desire to become Student Council President, and Tanukichi through his desire to get closer to Anna. Another similarity which comes naturally due to the nature of Shimoneta, is the presence of ecchi tropes and situations, extending to the usual mild nudity. How chaste.

15-year-old Yamada is a beautiful high school girl attending Takizawa High whose current dream is to have casual sex with 100 men. Despite her lofty goals, Yamada is very self-conscious and faces a dilemma – she wants to have sex, but she believes her vagina looks weird and to top it all off, Yamada has no experience whatsoever when it comes to sex. Her solution? Fellow high school student and classmate Kosuda Takashi, a fellow virgin and Yamada’s first stumbling block on her path to sexual enlightenment.

B Gata H Kei takes us on a twelve-episode journey with sex-crazed Yamada and her often clumsy attempts to seduce Kosuda and this is quite similar to the inexperience of newlyweds Izumi and Wakana. The most obvious similarity between both shows is their employment of ecchi and again, the running theme of school life extends to B Gata H Kei as well. Like Okusama ga Seitokaicho, B Gata H Kei closely follows the maturation of a relationship between a girl and boy under humorous circumstances. Ecchi-kei.

One day, while on holiday visiting his grandmother on the Seto Islands, Michishio Nagasumi has a near-death experience, nearly drowning in the sea. Having been saved by Seto Sun a mermaid, Nagasumi’s normal life changes forever as Sun’s yakuza mermaid family, the Seto Clan, offer him an ultimatum: his life or Sun’s, as per the Seto Clan’s rules. Caught between a rock and a hard place, the only way out for Nagasumi is for him to become part of the Seto Clan and marry Sun. Thus begins Nagasumi’s not-so-normal life as the husband of a mermaid and his everyday struggle to keep Sun’s mermaid identity a secret.

At a glance, one can spot the similarities between Okusama ga Seitokaicho and Seto no Hanayome – both titles allude to a character being someone’s wife and therefore both anime deal with the theme of marriage. Both sets of characters are in their teenage years and therefore have to juggle marriage and the everyday problems faced by high schoolers. With marriage being a central theme, one must also note the fact that in both anime, the concept of marriage is presented to the protagonist in a way that leaves him in no position to refuse, although Izumi Hayato’s situation is a lot less dire than Nagasumi’s.

When Suminoe Keita’s mother passed away, his father remarried and with his new wife came twin sisters Ako and Riko. However, ever since they first met him, Ako and Riko have harboured romantic feelings of love for their step-brother Keita. Now going into high school, Keita has his hands full with studying hard to enter his sisters’ high school, staving off their sexual advances, and resolving his conflicted feelings about them. Unfortunately for Keita, with increasing scores of women lusting after him, his will is tested as he consistently experiences temptation. Will Keita buckle under increasing pressure?

Kiss x Sis is a fairly standard harem anime. Besides the main character’s somewhat incestuous relationship with his sisters, Kiss x Sis contains many ingredients that make for an ecchi harem. But, Kiss x Sis begins to show its similarity to Okusama ga Seitokaicho in the main characters’ living situation: with Keita’s dad always out of the house, he lives alone with his sisters, much like Izumi Hayato lives alone with his wife Ui. In both anime, the plot is created by the decision of a parent, and both anime feature a school setting and copious amounts of ecchi to service any fan. Did we mention the ecchi?