Mysterious Girlfriend X
|Mysterious Girlfriend X|
Cover of the first manga volume
(Nazo no Kanojo Ekkusu)
|Genre||Romantic comedy, school story, slice of life, supernatural|
|Written by||Riichi Ueshiba|
|Original run||August 23, 2006 – September 25, 2014|
|Anime television series|
|Directed by||Ayumu Watanabe|
|Written by||Deko Akao|
|Music by||Tomoki Hasegawa|
|Network||Tokyo MX, AT-X|
|English network||Anime Network|
|Original run||April 7, 2012 – June 30, 2012|
|Original video animation|
|Directed by||Ayumu Watanabe|
|Written by||Deko Akao|
|Released||August 23, 2012|
Mysterious Girlfriend X (謎の彼女X Nazo no Kanojo Ekkusu?) is a Japanese manga written and illustrated by Riichi Ueshiba. It was originally published as a one-shot story in 2004 before becoming a serialized comic in Kodansha's Afternoon magazine in 2006. An anime adaptation by Hoods Entertainment aired in Japan from April 7, 2012 to June 30, 2012, with an original video animation episode released on August 23, 2012.
The series follows the relationship of Akira Tsubaki and Mikoto Urabe. Urabe is a transfer student who recently came to Tsubaki's school. After a series of strange events, Tsubaki finds himself addicted to Urabe's drool. Once she claims the addiction as love sickness, the relationship slowly progresses, focusing on the odd bond that comes out of the drool attachment.
- Mikoto Urabe (卜部 美琴 Urabe Mikoto?)
- Voiced by: Ayako Yoshitani (Japanese), Genevieve Simmons (English)
- Urabe is the titular Mysterious Girlfriend and the main female protagonist of this series. Very little is known about her, as Tsubaki's occasional visits to her apartments have never shown her parents to be around. She initially transfers to Tsubaki's school and gives off an unsocial air, refusing to eat lunch with her classmates in order to sleep. One day, she breaks out in hysterical laughter during class, falling to the ground. When later telling Tsubaki about it, she reveals to him that she heard a voice saying that he would be her very first intimate partner.
- Urabe is very knowledgeable about the bond of drool that she and Tsubaki share. She displays her feeling through her drool, as her face is generally hidden behind her bangs. She has been shown to see Tsubaki's dreams through his drool, as well as use her own drool to cause him to have certain dreams. As the series progresses, she makes friends with Ayuko Oka, who also happens to share a drool bond with Urabe. Although she generally keeps quiet about her private life, she has been shown to be very sincere to her boyfriend, Tsubaki.
- Among her many other quirks, Urabe is notable for her skill with scissors. The scissors, which she keeps tucked in her underwear, can be used to dextrously cut objects at high speed, like making a nearby hedge resemble Tsubaki. The scissors are used as threats, displays of anger, and as a defensive measure. This is but one of the factors that keeps Tsubaki from being more forward and aggressive with their relationship, although he seems to be generally fine with following Urabe's pace.
- Akira Tsubaki (椿 明 Tsubaki Akira?)
- Voiced by: Miyu Irino (Japanese), Josh Grelle (English)
- The main male protagonist, Tsubaki is an average boy by most standards. He lives with his sister and his father. His mother died when he was very young, prompting his sister to fulfill the motherly role instead. When Urabe transfers into his class, he is initially intrigued by her, particularly after one outburst of her hysterically laughing. After school one day, he wakes Urabe up from her desk, only to find a puddle of drool left behind. Absent-mindedly, he takes some on his finger and tastes it. Shortly afterwards, he falls ill. When Urabe visits him, she claims that he is suffering from "love-sickness", which he most likely got from tasting her drool. From there, the relationship begins, and Tsubaki quickly asks Urabe to be his girlfriend. Although she accepts, he continually feels that there is too much distance between them. Although they rarely have any physical contact, the two begin a ritual where Tsubaki tastes a bit of Urabe's drool each day. The drool can transmit feelings, among other things, between the two of them.
- Tsubaki is not very aggressive in his pursuit of furthering his relationship with Urabe, slightly due to his fear of Urabe's scissors. He constantly compares his relationship to Kouhei's and Ayuko's, and will occasionally try to emulate them. He develops a taste for girls who look like Urabe, as evidenced by his collection of Urabe look-alike Japanese idol Momoka Imai's photos. Eventually she cuts them up with a double scissors attack.
- Ayuko Oka (丘 歩子 Oka Ayuko?)
- Voiced by: Ryō Hirohashi (Japanese), Brittney Karbowski (English)
- Ayuko is Kouhei's girlfriend and Urabe's eventual friend. She was first introduced when Tsubaki walked into his homeroom to see her and Kouhei kissing together. She is rather short (143cm tall), yet she has a body which resembles a model, which she seems to enjoy on occasion when she dresses her favorite clothes out of her boyfriend's permission. After she sees the drool-tasting ritual between Tsubaki and Urabe, she befriends Urabe, and it's revealed that they share a drool bond as well. Ayuko is portrayed as slightly lecherous, given by her positive reaction to peeking down Urabe's blouse. She views her relationship with Kouhei almost as a competition with Urabe and Tsubaki.
- Kouhei Ueno (上野 公平 Ueno Kōhei?)
- Voiced by: Yūki Kaji (Japanese), Greg Ayres (English)
- Kouhei is Tsubaki's friend and Ayuko's boyfriend. When Tsubaki first walked in on him and Ayuko kissing, Kouhei asked him to keep their relationship a secret, as he is rather shy about it. He helps Tsubaki by providing advice about relationships. Kouhei is shown to be very jealous of Ayuko, and doesn't like the idea of taking her to the beach. He also tries to keep some control by dressing her more conservative in order to avoid other boys from seeing her.
- Youko Tsubaki (椿 陽子 Tsubaki Yōko?)
- Voiced by: Misato Fukuen (Japanese), Carli Mosier (English)
- Tsubaki's elder sister. She considers it her duty to raise her brother properly in place of their deceased mother, and refuses to consider getting married until he graduates and finds a job. She spends her time housekeeping. Tsubaki's occasional strange behavior from the effects of Urabe's saliva sometimes makes Youko worry about her brother. Youko has met Urabe, but has not been told of the full extent of her relationship with Tsubaki. Urabe said she was only a classmate Tsubaki helps often at school, though some dialogue suggests she knows the truth. Urabe told her in chapter 85 of volume 10 in the bath house.
- Aika Hayakawa (早川 愛香 Hayakawa Aika?)
- Voiced by: Yū Shimamura (Japanese), Cynthia Martinez (English)
- A beautiful, long-haired girl who was Tsubaki's classmate and first crush in middle school. She knew of his feelings for her, but never told him, and attended a different high school after graduation. Out of all of the cast she has a very possessive personality, faking a bruise to trick Tsubaki to pretend to be her boyfriend for a day and setting it up so Urabe will come to the festival during that time. However, after clearing up everything with her boyfriend they returned to being a couple again. Another note is that she and Tsubaki have similar quirks.
- Ogata (緒方 Ogata?)
- Voiced by: Takahiro Mizushima (Japanese), Chris Patton (English)
- A popular, good-looking classmate of Tsubaki and Urabe who is also a star player of the school soccer team. He is interested in Urabe, and tries to ask her out, but she turns him down because, unlike Tsubaki, his body has no reaction to her drool.
- Matsuzawa (松沢 Matsuzawa?)
- An attractive, short-haired schoolmate of Tsubaki who is one grade below him. She and Tsubaki met through the school film club. She likes Tsubaki because they share unusual tastes in movies. Although Tsubaki in turn enjoys talking to her, he worries that the attention she gives him will make Urabe jealous. Later she is announced to be the film club vice president in the chapter Mysterious Film Club Production.
- Momoka Imai (今井 百夏 Imai Momoka?)
- A media idol who looks almost identical to Urabe, except that she has brown hair and much smaller breasts. She makes an appearance in Chapter 37, and seems to have much more in common with Urabe than one would expect, though more energetic. Like how Urabe uses scissors on people, she kicks, though she wears restraints, however both are located where their panties are. She sought out Urabe in hopes she will agree to her plan of switching between model and student, however Urabe completely turns her down. After accidentally knocking her out (and Urabe cutting off all of her clothing), she discovers the difference in their breast sizes, seeming to have a changed her mind after discovering this. After seeing Urabe and Tsubaki's bond, she goes with her promise and lets go of her plan to switch places, however not before stealing Urabe's uniform and going to make Tsubaki taste her drool. It is revealed she wanted to become a "normal" girl due to an incident with a boy she had a crush on before she became famous. Then after being discovered and becoming famous, she finally gained up the courage to confess her feelings to him, but before they kissed he asked if he could tell his friends he was dating a famous girl. Realizing he only liked her because she was famous, she high kicked him in the head.
- Yoshikawa (Yoshikawa)
- The idol of class 2-C.
- Suwano Ryouko
- Tsubaki and Urabe's beautiful classmate. She seems to have a crush on Tsubaki and frequently drops hints about that. Being responsible for collecting the class handouts along with Tsubaki, both of them have to stay back after school sometimes. This makes their other classmates think that they both like each other. According to Tsubaki, Suwano has ″gentle soothing eyes″. Suwano is one of the few people who know about Tsubaki and Urabe's ″drool relationship″. Suwano is good in swimming and has a flair for dramatics too. She later gets a boyfriend in a chapter called Mysterious Shutter Chance.
|01||August 23, 2006||ISBN 978-4-06-314424-6|
|02||June 22, 2007||ISBN 978-4-06-314457-4|
|03||February 22, 2008||ISBN 978-4-06-314490-1|
|04||November 21, 2008||ISBN 978-4-06-314539-7|
|05||August 21, 2009||ISBN 978-4-06-314583-0|
|06||June 23, 2010||ISBN 978-4-06-310673-2|
|07||February 23, 2011||ISBN 978-4-06-310729-6|
|08||February 23, 2012[dead link]||ISBN 978-4-06-387806-6|
|08CD||February 23, 2012||ISBN 978-4-06-358385-4|
|Drama CD version of volume 8's release, with Anime VA cast|
|09||August 23, 2012[dead link]||ISBN 978-4-06-387835-6|
|09DVD||August 23, 2012||ISBN 978-4-06-358391-5|
|Special edition manga release of volume 9 including Anime DVD|
- 072 "The Mysterious Fruit"
- 073 "The Mysterious Christmas"
- 074 "The Mysterious New Year's"
- 075 "The Mysterious Valentine"
- 076 "The Mysterious White Day"
- 077 "The Mysterious Soft Ball Game"
- 078 "The Mysterious One Piece"
- 079 "The Mysterious Poolside"
- 080 "Mysterious Fireworks"
- 081 "The Mysterious Backstory"
- 082 "Mysterious Tennis Court"
- 083 "This Story's Slightly Mysterious Beauty... That's Suwano"
- 084 "Tsubaki vs Urabe"
- 085 "That Day, The Fragments of the Sky were White"
- 086 "Mysterious Shutter Chance II"
- 087 "Mysterious Cologne"
- 088 "Mysterious 'Rut'"
- 089 "Mysterious Curried Rice"
- 090 "Mysterious Shopping"
- 091 "Mysterious Sunset (Part 1)"
- 092 "Mysterious Sunset (Part 2)"
An anime adaptation by Hoods Entertainment aired in Japan between April 7, 2012 and June 30, 2012 and was simulcast by Crunchyroll. An original video animation episode was released with the ninth volume of the manga on August 23, 2012. The series has been licensed in North America by Sentai Filmworks and began streaming on The Anime Network and Hulu 31 days following its airdate. Sentai Filmworks released a box-set containing the entire 13 episode TV series on Blu-ray and DVD June 11, 2013. The opening theme is "Orchestra of Love" (恋のオーケストラ Koi no Ōkesutora?) by Ayako Yoshitani, whilst the ending theme is "Afterschool Promise" (放課後の約束 Hōkago no Yakusoku?) by Yoshitani. An English dub was released in Australia by Hanabee Entertainment on June 5, 2013. 
|No.||Title||Original air date|
"Nazo no Kanojo" (謎の彼女)
|April 7, 2012|
|A strange new transfer student named Mikoto Urabe is instantly labelled as a weirdo due to her odd sleeping patterns and a strange outburst of laughter during class. When Akira Tsubaki wakes up Urabe at the end of a school day, he finds her face enchanting and ends up sampling some of her drool. After having a dream about Urabe that he can't seem to get out of his head, Tsubaki suddenly comes down with fever. Urabe goes to Tsubaki's house and gives him more of her drool which cures his fever, explaining his symptoms were the result of withdrawal from not getting any more drool. As such, Urabe begins meeting up with Tsubaki every day to give him some more of her drool. As Tsubaki starts to fall in love with Urabe, he decides to confess to her after a few days. When asked by Urabe to profess his love in a way only he can, Tsubaki demonstrates it by ripping up a photo he had in his wallet of his middle school crush. After explaining the reason she laughed in class was because a voice told her Tsubaki would be the first person she would have sex with, Urabe agrees to become his girlfriend.|
"Nazo no Kizuna" (謎の絆)
|April 14, 2012|
|Tsubaki decides to ask his friend, Kouhei Ueno, what he could do to advance his relationship with Urabe, though none of his advices seem to work on Urabe. When asked if they really are in a relationship or not, Urabe takes Tsubaki to an abandoned house. She tells Tsubaki to close his eyes and then she undresses, and then feeds Tsubaki her drool, explaining that their drool is a special bond that allows them to know what they are feeling. The next day, after Tsubaki has a strange dream involving Urabe, Urabe drinks some of Tsubaki's drool and somehow manages to recall his dream in great detail.|
|03||"Mysterious Test Tube"
"Nazo no Shikenkan" (謎の試験管)
|April 21, 2012|
|Tsubaki spots Kouhei kissing Ayuko Oka, who Kouhei explains is his girlfriend, whom he's been secretly dating for a while. When Tsubaki expresses his desire to kiss Urabe, she gives him a testtube of her drool, telling him to drink it before he goes to bed. That night he has a dream where he is accidentally kissed by Urabe, feeling disappointed that she isn't putting her feelings into it. The next day, Tsubaki comes to realise they should only kiss when they come to understand each other's feelings. Later at school, another boy in Tsubaki's class, Ogata, confesses to Urabe, asking her to go out with him. Urabe decides to give him a reply the next day, forbidding Tsubaki to interfere. The next day, she feeds Ogata some of her drool and, upon hearing he doesn't feel any different, rejects him. After doing the same with Tsubaki, which makes his nose bleed, because she was not wearing underwear that day, Urabe explains how his reaction to her drool is proof that he is the only one she shares this bond with, and they walk home together holding hands.|
|04||"Mysterious Girl meets Girl"
"Nazo no Gāru Mītsu Gāru" (謎のガール・ミーツ・ガール)
|April 28, 2012|
|Ayuko decides to have her lunch next to Urabe, much to everyone's surprise. As Urabe gets a scrape during PE the next day, Ayuko takes her to the nurse's office to treat it. After sharing a drink with her, Ayuko discovers she suddenly has the same injury as Urabe. They soon deduce that Urabe's drool can also transfer injuries, showing Ayuko has a similar connection to her as Tsubaki does. Ayuko mentions how she became fascinated by Urabe after seeing her with Tsubaki, but Mikoto rejects her offer of becoming friends. The next day, Ayuko feeds some of her drool to Urabe, deducing from her reaction to its sweet taste that she hasn't kissed Tsubaki yet. Afterwards, Urabe and Ayuko begin a daily routine of having lunch together.|
|05||"Mysterious First Date"
"Nazo no Fāsuto Dēto" (謎のファーストデート)
|May 5, 2012|
|After failing to see Urabe in a swimsuit during swim class, Tsubaki sees an image of her in a swimsuit while tasting her sweat. As summer vacation arrives and the two continue their drool swapping tradition, Tsubaki manages to build up the courage to ask Urabe on a date to the beach. A week passes and Tsubaki and a tanned Urabe head to the beach where they eat yakisoba and swim in the ocean. Upon spotting a tanline from Mikoto's pair of scissors, Tsubaki gets a nosebleed which Urabe later experiences when she tries Tsubaki's drool on the way home.|
|06||"Mysterious Step Up"
"Nazo no Suteppu Appu" (謎のステップ・アップ)
|May 12, 2012|
|While shopping for clothes, Tsubaki is met by Ayuko who talks to him about using first names with her boyfriend, Kouhei. Ayuko deduces that Urabe and Tsubaki do not use each others' first names via an abridged drool swapping with Tsubaki. She then accosts Urabe similarly and talks to her about first names briefly before Urabe excuses herself. At the park Tsubaki preys upon a sleeping Urabe by whispering her first name "Mikoto" to her. Tsubaki has another weird dream again and blurts out that he wants a photo of Urabe when they are walking to school. Later, Tsubaki is waiting for Urabe at a bridge and his old crush, Aika Hayakawa, invites him to a coffee date. After he declines the invitation, Tsubaki finds Urabe hiding at one of the bridge ends and says she did not want to interrupt the conversation. While walking back, Urabe and Tsubaki talk about Tsubakis's crush. After a drool swap, the two understand each others feelings before Tsubaki whips out the camera again to try and take a photo of Urabe who lets him take a picture with her tongue sticking out.|
"Nazo no Hayarikaze" (謎の流行風邪)
|May 19, 2012|
|After showing impressive display on the track, Urabe is asked to participate in a relay race for the sports festival, although she rejects the idea of joining the track team as it means she wouldn't be able to walk home with Tsubaki. As the students switch to their winter uniforms, Tsubaki comes down with a cold. Having heard from Ayuko about how she dressed up in a bikini to help Kouhei get over a cold, Urabe secretly wears a bikini under her coat and gives Tsubaki some of her drool, which helps him recover. On the day of the sports festival, Urabe manages to help bring her team to victory in the relay race. Tsubaki suggests to Urabe that she should join the track team, but Urabe once again rejects, as she much prefers spending time with Akira.|
"Nazo no Kankaku" (謎の感覚)
|May 26, 2012|
|Tsubaki has a dream where he got to squeeze Urabe's breast and can't get the sensation out of his head. Taking a stroll, he decides to go in the direction Urabe usually takes after school and comes up to an apartment block, which turns out to be where Urabe lives. Urabe invites Tsubaki into her apartment for tea, where his imagination starts to get the better of him. After catching Mikoto as she trips after being spooked by some lightning, Tsubaki almost reaches for her breast but Urabe stops him. After getting Tsubaki to tell her about his dream, she feeds him some drool whilst grabbing her own breast, giving him a stronger sense of the feeling. She then allows Tsubaki the opportunity to touch them for himself, which causes Tsubaki to become more aggressive and tease her ears until he notices Urabe is crying and leaves. The next day, after Urabe gets some advice from Ayuko about the new experiences she is feeling, Tsubaki asks Urabe to slap him as a way of apology. Afterwards, Urabe explains the feeling she gets when her ear is touched before taking on Tsubaki's bruise herself.|
|09||"Mysterious "This is just, I dunno...""
"Nazo no "Nandaka Chotto"" (謎の「なんだかちょっと」)
|June 02, 2012|
|Noticing Urabe with a serious case of bedhead, Ayuko fixes her up with a new hairstyle. Urabe soon gets a lot of attention for her new hairstyle, which makes Tsubaki a bit jealous. As they go home, Tsubaki convinces Urabe to go back to her old hairstyle and messes up her hair on her request. The next day, as Ayuko calls her out on it, Urabe shows her the feeling of having her hair messed up, which she comes to enjoy. Meanwhile, as Tsubaki gets frustrated when one of the male students starts selling photos of Urabe's alternate hairstyle, he learns of an idol named Momoko Imai who has a strong likeness to Urabe. Tsubaki soon impulsively buys Momoko's photobook and enjoys looking at it. As Urabe hears about it from Ayuko, who heard about it from Kouhei, she demands Tsubaki to bring the book to her and destroys it with her scisssors, saying he doesn't need it when he's got the real deal.|
"Nazo no Abanchūru" (謎のアバンチュール)
|June 09, 2012|
|Tsubaki runs into Aika who, having just been dumped by her boyfriend, reveals how she knew of Akira's feelings for her when he lies about not having a girlfriend. Aika gives Tsubaki the opportunity to try some of her drool, but he backs out realising it could damage his bond with Urabe, bringing to light that he does have a girlfriend. The next day, Aika decides to approach Urabe, inviting her to her school's culture festival on Sunday with the news that Tsubaki might be there. Later that night, Aika calls out Tsubaki with a fake wound on her face, manipulating Tsubaki into coming to the festival with her and pretending to be her boyfriend. Tsubaki tries to come up with an alibi in front of Urabe, but she soon learns the truth from Ayuko. As Tsubaki goes to the festival on Sunday, Aika shows up wearing her old middle school uniform.|
|11||"Mysterious Cultural Festival"
"Nazo no Bunkasai" (謎の文化祭)
|June 16, 2012|
|As Ayuko goes to the festival with Kouhei, she spots Tsubaki with Aika and decides to follow them. As Tsubaki tries to hold off the advances of Aika, Urabe appears in a box robot, suggesting they do a blind taste test of each of their drool to see which Tsubaki prefers. Akira instantly gets a nosebleed from Urabe's drool, due to the fact that she was naked inside her costume. Aika gets naked and attempts to give Tsubaki her drool, but she stops when she starts crying, making it clear that her advances on Tsubaki were simply an attempt to get over losing her boyfriend, who had feelings for someone else even when he was dating her. Urabe tries some of Aika's drool, sensing she has long had unrequited love but assuring her she'll one day find the right someone. Just then, Tsubaki's blindfold gets shaken off and he sees the girls naked, prompting slaps from the both of them. As Tsubaki and Urabe leave together, she tells him that her eventual kiss with him will be her first, prompting a smile when she tries his drool.|
"Nazo no "Gyu"" (謎の「ぎゅっ」)
|June 23, 2012|
|As Tsubaki is a little bashful around Urabe after having seen her naked, she requests to try his drool to experience how flustered he is. The next day, when Urabe uses her scissors against Tsubaki for attempting to hug her, she is shocked when she sees she had cut his forehead a little. As Urabe takes Tsubaki to her home to get his injury treated, she finds her scissors have become less accurate, which she believes to be caused by a strange dream she had after trying Tsubaki's drool. As Urabe gives Tsubaki more of her drool, he starts picturing Urabe naked and ends up banging his head whilst trying to avoid hugging Urabe on impulse. After hearing his reasoning, Urabe decides to hug Tsubaki of her own accord, which in turn restores her scissor technique. The next day, as Ryouko Suwano (諏訪野 亮子 Suwano Ryōko?), one of his classmates, offers to replace Tsubaki's gauze, Tsubaki opts to keep it as it was the gauze Urabe gave him. Later that day, Urabe once again initiates a hug.|
|13||"Mysterious Girlfriend and Boyfriend"
"Nazo no Kanojo to Kareshi" (謎の彼女と彼氏)
|June 30, 2012|
|While out shopping, Urabe meets up with Tsubaki's sister, Youko, who takes her to a coffee shop, where she talks about past love crushes and asks about having a boyfriend. She mentions that she promised her deceased mother that she will take care of Tsubaki until he finishes his studies, and so does not have time for romances. Later on, Urabe asks Tsubaki to go to his mother's grave next Sunday and pay their respects. Urabe meets with Tsubaki and he's surprised to see her very formally dressed. After paying their respects and talking about Tsubaki's mother, Urabe wants to "feel" Tsubaki's memories about his mother and they decide to simultaneously exchange drool while Urabe touches the gravestone. Urabe and Tsubaki both end up shedding tears and they feel that their bond has deepened as they continue to walk off talking and laughing.|
|OVA||"Mysterious Summer Festival"
"Nazo no Natsu Matsuri" (謎の夏祭り)
|August 23, 2012|
|Tsubaki, Urabe, Kouhei and Ayuko go together to the summer festival. As Kouhei and Ayuko go off together, Tsubaki and Urabe are left on their own, but get separated in the crowd, with Urabe being led away by a mysterious masked girl. As Tsubaki searches for her, he comes across a strange tent where Urabe is found tied up. Tsubaki is then challenged by her kidnappers to pull a rope to free her, pulling the wrong one causing her to fall. Believing in their bond, Urabe drools down the rope she is tied up against, allowing Tsubaki to deduce the correct rope to pull. After Tsubaki frees Urabe, the kidnappers and the tent mysteriously disappear and Tsubaki and Urabe find themselves at the shrine, where Urabe gives Tsubaki a red string bracelet.|
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- Riichi, U: "Mysterious Girlfriend X", Vol 2, pages 166-167. Afternoon KC, 2004. ISBN 978-4-06-314457-4
- Riichi, U: "Mysterious Girlfriend X", Vol 3, Afternoon KC, 2008. Ch. 19, 9-11. ISBN 978-4-06-314490-1
- Riichi, U: "Mysterious Girlfriend X", Vol 1, Afternoon KC, 2004. Ch. 4, 6-10. ISBN 978-4-06-314424-6
- Riichi, U: "Mysterious Girlfriend X", Vol 2, Afternoon KC, 2004. Ch. 9, 3-9. ISBN 978-4-06-314457-4
- 謎の彼女Ｘ(1) [Mysterious Girlfriend X (1)] (in Japanese). Kodansha. Retrieved June 30, 2010.
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- 謎の彼女Ｘ(3) [Mysterious Girlfriend X (3)] (in Japanese). Kodansha. Retrieved June 30, 2010.
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- 謎の彼女Ｘ(6) [Mysterious Girlfriend X (6)] (in Japanese). Kodansha. Retrieved June 30, 2010.
- 謎の彼女Ｘ(7) [Mysterious Girlfriend X (7)] (in Japanese). Kodansha. Retrieved April 15, 2012.
- 謎の彼女Ｘ(8) [Mysterious Girlfriend X (8)] (in Japanese). Kodansha. Retrieved April 15, 2012.
- "謎の彼女Ｘ(8CD)" [Mysterious Girlfriend X (8CD)] (in Japanese). Kodansha. Retrieved April 15, 2012.
- "謎の彼女Ｘ(9DVD)" [Mysterious Girlfriend X (9DVD)] (in Japanese). Kodansha. Retrieved April 15, 2012.
- "Sentai Filmworks Adds Kids on the Slope, Mysterious Girlfriend X". Anime News Network. 2012-04-07.