After considering many opinions across the internet and consulting with fellow yuri (百合, lesbian themed Japanese media) fans, these are the seven best examples of non-explicitly erotic girl-on-girl animation from Japan.
Oniisama E actually ranks lower on this multi-person synthesised list than it does on my personal list (where it comes in at #5). The series centers around the high school experiences of Misonou Nanako (note: for this and subsequent names, family name comes first) when she enters the elite preparatory school, Seiran Academy. The series deals not only with issues of lesbianism, but also issues of suicide (still very relevant given the high rates amongst LGBT+ youth), mental health, substance abuse, domestic violence, and incest. For those who might be expecting overt romance, however, they'll be disappointed. As Yuricon's Erica Friedman points out, the series deals more with akogare (yearning) than it does with actual romance.
There is a great deal of akogare in this series, and very little outright Yuri, but I'm going to have to weigh in on the yes, Yuri camp.
There are better works which deal with queer themes by Oniisama E's artist, Ikeda Riyoko, but none are (in my opinion) amongst those which have been animated. Most people tend to think of The Rose of Versailles or Ace wo Nerae. However, in both cases, the yuri elements are quite minor. Like most classic yuri, Ikeda's works which do deal with female/female relationships are pretty tragic. Indeed, ultimately, they are depressing in the extreme. This is largely because of the influence of the Class S novels of the early twentieth century, exemplified by the works of Yoshiya Nobuko.
Her stories of dosei-ai (same-sex love) and of female friendships had a direct influence on later Shōjo manga. In particular, her works often fall in line with the Class S genre, which depict lesbian attachments as emotionally intense yet platonic relationships, destined to be curtailed by marriage, school, or death.
While the relationships depicted aren't always "platonic," with plenty of them making their way into actual "forbidden" relationships, the tragic nature of this classic yuri trope means the death and/or utter despair of the "transgressing" characters. Oniisama E certainly walks this line to great effect.
Simoun is a world where gender and sexuality, not to mention biology, just do not work in the same ways as in our own. On the planet Daikuriku, all people are female. Only at seventeen do they choose a "permanent" sex, either male or female. As with many anime series, the trope at play here is teenager pilots: people who have chosen a "permanent" sex cannot pilot the airships which protect the nation state of Simulacrum.
Each of the Simoun airships requires a pair of girls to pilot it. As all of the teenagers in the series have grown into female puberty to some extent by the age of seventeen, any romantic or sexual feelings towards peers would obviously be "same-sex." And the romantic entanglements between the pilots is a major part of the character interaction. However, given the nature of how gender, sexuality, and biology function in Simoun, some argue the series isn't actually yuri. Ironically, this is what makes Simoun such an interesting series to watch, despite its "fanservice" moments and the general style of its character designs. It leaves you questioning what relationships are heterosexual, what relationships are homosexual, and what relationships simply are or should be simply un-labeled.
Unlike the previous two series, Sasemeki Koto is unabashedly yuri. The main characters in the series are all pretty much self-identified lesbians, aside from the one recurring male (but possibly gender-variant) character.
Kazama Ushio (on the right) isn't shy about announcing that she's interested in other girls, and she often bemoans that homosexuality is still taboo in Japanese society. She specifically says she prefers "cute," "feminine" and "shy" girls. This turns out to be problem for her best friend, Murasame Sumika (on the left), who is secretly in love with Ushio and is anything but "cute," "feminine," or "shy."
One of the strongest aspects of the series is in the subtle message that there is strength in shared experiences. For both Ushio and Sumika being gay is isolating in the straight society represented both in high school and the wider culture. Discovering that they are not the only queer students in their high school with the formation of what essentially becomes a de facto queer student group called the "Girls' Club," turns out to be very beneficial to Ushio and Sumika as they fumble towards each other in a typical angsty teenage manner.
To be fair, I'm not actually a huge fan of Sasameki Koto. For me, having seen it after Aoi Hana, I have real trouble not comparing the two. This is especially true because there are similarities in physical features, although not so much in personality, between the two main characters. However, it is incredibly popular, which explains both its inclusion on this list and the place it holds.
Adapted from a series of "light novels," there's no question that Maria-sama ga Miteru (Marimite for short) is the modern day successor to the Class S novels, especially Yoshiya's Hana Monogatari. Marimite centers around a group of students at a fictional elite Tokyo Catholic school who make up the school's student council. The language, the style, the clothing, and the symbology are all "high" yuri, evoking imagery strongly associated with yuri history.
The series embodies the previously mentioned akogare (yearning) of the Class S novels, and like Oniisama E, "depicts lesbian attachments as emotionally intense yet platonic relationships, destined to be curtailed" by marriage or school (or potentially early mortality), specifically by graduation and the events which occur after graduation. Senior members of the student council take on "seours" or "sisters" from the lower grades who will then be expected to succeed them in their positions.
Narratives focuse on the strong bonds which develop between the girls, especially between Ogaswara Sachiko and Fukuzawa Yumi (seen on the left). Initially Yumi is not interested in becoming Sachiko's "petite soeur" and Sachiko must work to convince her to accept her rosary, the sign of a "petite soeur." The vast majority of the plot is devoted to Sachiko and Yumi, and they can definitely be viewed as the primary characters of the series. Sachiko has a terrible phobia of men, although she is willing to put that aside if her devotion to Yumi requires her to do so.
Hasekura Rei and Shimazu Yoshino (seen on the right) are actually probably my favorite pairing. An obvious complementary pair both physically and in personality, they also are the only pair which really challenges the "platonic" aspect of the Class S tropes. It becomes rather apparent very quickly that while they are rare to show overt romantic affection, they see each other as soul mates and are deeply in love. Yoshino, especially, is prone to childish fits of jealousy.
The strength of the series, which can seem overly styled or even boring to some, is in the potential for breaking out of the Class S and classic yuri tropes: will they or won't they survive the tropes? You won't know until you watch until the end.
It's difficult to give Shoujo Kakumei Utena (or just Utena) any kind of adequate summary. It is a series even a hardcore yuri or anime scholar could watch over and over again and still find more to analyse. In addition to haunting visuals and an eerie soundtrack, the series borrows tropes not just from classic/high yuri, but also the magical girl genre, and shoujo more generally. It also just happens to be third on my personal list of favorite anime in general, not just yuri.
There's no way around it: Utena is strange. Very strange. And giving any kind of summary really risks spoiling it for potential new viewers because of just how many mysteries there are about the setting, its history, the characters, their relationships, and their motivations.
The series begins sometime after the transfer of 14 year old Tenjou Utena to the elite Ohtori Academy. The anime doesn't explain how she got there, but the manga (comic) does (if you're curious). Athletic and tomboyish in attitude, Utena wears feminised version of the Ohtori boys uniform. Although she strongly articulates her gender identity is not in question, she also reveals her dream is to become a prince like the one who rescued her in childhood and gave her a ring: a ring with the same rose crest as the school.
Owing both to her goal to become a prince and her inner sense of nobility, she comes to the aid of her friend Wakaba (who often jokingly refers to Utena as her boyfriend, despite actually being straight) when the latter girl is humiliated by her love interest: school council vice president and kendo practitioner Saionji Kyouichi. Mistaking Utena for a mysterious new "duelist," he meets her at a special location behind the school where Utena meets Himemiya Anthy, the "Rose Bride," who has the "Power to Revolutionise the World." An overconfident Saionji loses the duel, despite the fact he has a katana sword and Utena only has a wooden practice version. Having "won" Anthy, Utena finds herself followed home by the mysterious "Rose Bride."
The series focuses on Utena's attempts to protect Anthy at all costs from the other members of the student council, as well as other various duelists which appear. She struggles to reconcile both her masculinity, as a prince-to-be, and her femininity as a previously rescued princess, and to identify her feelings towards Anthy as well as towards male suitors. Above all, she is determined to unravel the mysteries of the prince and the setting around her.
Worth mentioning that Utena and Anthy are hardly the only (potentially?) queer characters in the series. Unfortunatey, too much detail would spoil some of the best revelations about members of the cast. Utena is just that complex that it's very easy for cursory identifications to give away important plot details.
Other yuri reviewers have drawn comparisons between Utena and The Rose of Versailles by Ikeda, and while that is visually true (largely due to costuming), I feel that the series is drawing much more from the world of Oniisama E and its representation of the Class S tropes. Many of the same issues found in that earlier series can be found in Utena, just wrapped up in the latter series' unique visuals, absurd settings, and convoluted reality.
Watch this one at least twice. You'll be surprised what you missed the first time around.
Unlike the other series on this list, Noir is not connected to classic or high yuri and not connected to Class S tropes. In fact, it's not even explicitly yuri canonically. While yuri subtext is pretty clear to many (and is even clearer in the series' spin-off), Noir is just damn good fun where the focus is on an extremely strong relationship between the two female characters. What puts this anime so far up on the list is that it's extremely well done for an anime series in general.
The plot centers around two seemingly unrelated assassins, Mireille Bouquet and Yuumura Kirika. As the series progresses the two learn more about their connection and why they are being pursued by an Illuminati like organisation knows as Les Soldats (The Soldiers in French). With a pair of female assassins who oppose Mireille and Kirika, the series is very overtly female-centric.
Up your alley if you like implied lesbians with heavy firepower.
Aoi Hana seems undeniably the most realistic depiction in anime of lesbian relationships amongst adolescents in Japan. It's painful to watch in many ways, although it never gets to the sort of tropey melodrama of its predecessors, and intentionally so. Creator Shimura Takako uses the understated and realistic style of Aoi Hana to challenge the tropes of the yuri genre.
This story centers around Manjoume Fumi and Okudaira Akira. At first the main character appears to be Fumi, with A-chan a strong supporting character, as Fumi goes from one disastrous lesbian relationship to another, but it quickly becomes apparent that the one stability in Fumi's life is A-chan. The anime only goes up to this realisation, but the manga series (of which the anime comprises maybe a third or a fourth) has been focused on the development of the romantic relationship between the two.
The tropes Shimura tries to tackle are all those which have been previously mentioned in the above series, especially in Oniisama E and Marimite. In doing so, she draws a line between what is real in yuri and what is romantic fantasy. This includes the idea that girls' high schools are overrun with lesbians and that lesbian or lesbian-like relationships commonly exist prior to marriage in these schools. She also challenges the wider anime and manga trope that student/teacher relationships are common, resulting even in marriages, and that such relationships are accepted or even encouraged by the wider school society.
She certainly finds examples of each in the series, but the reader comes away with the distinct idea that these examples are rarities. And those rarities are not left unexplored. Rather, Shimura follows them to their real, practical conclusions, and readers are left staring at a world very unlike the one typically found in the closed off campuses of yuri girls' high schools and academies. What we find is ugly. Politely bigoted, but bigoted none-the-less. The world that is hostile to Fumi's sexuality and deeply uncomfortable with A-chan's sexual ambiguity.
Aoi Hana is slow. Very slow. This is often cited as a mark against it. However, this seems unfair and a misunderstanding of Shimura's purpose. It generally represents the same passage of time as actually covered in the amount of time it took to air on TV (or in the manga, to be produced). Since the focus is on showing a fairly realistic depiction of an adolescent lesbian relationship, much of the series shows details which don't "advance the plot." After all, most of our daily lives don't "advance a plot." The details simply exist, in reality, and most of those details are pretty boring. This is another challenge to the yuri trope that every action must be infused with dramatic meaning and have a deeper purpose.
Aoi Hana simply is. It humanises a relationship which is usually either considered too taboo to discuss openly or is tied so heavily into yuri literary and media tropes that it cannot be connected to lives of real, living people. And that's what makes the number one best series on this list.
Images via Ikeda Riyoko, Saitou Chiho/Be Papas, Be Train, Studio Deen, and Ikeda Takashi/AIC.