is a five-volume Japanese manga that was adapted as a 13-episode anime television series. It tells of a love affair between a man in his late twenties and his teenage sister.
The story focuses on the issue of genetic sexual attraction, a condition where two people who are related but have been apart may find themselves attracted to each other more than two complete strangers.
The manga, authored by Motoi Yoshida, was serialized in Kodansha's The Evening. The anime went into production before the manga was completed, and although the anime does not cover the events of the fifth volume, the endings are similar.
Koi Kaze was first broadcast on TV Asahi in 2004. However, the station only aired twelve episodes. The episode, "Dew Frost", was later made and streamed on the official Geneon website. It has aired in reruns and included in the DVD release as the eighth episode.
Koi Kaze was released on DVD in North America by Geneon in 2005. This is one of the first mainstream anime series about incest — here, a romantic relationship between siblings — to be widely marketed in the U.S.
Born twelve years apart, siblings Koshiro and Nanoka were separated when their parents divorced and moved to different parts of Japan; as a result, they both grew up hardly aware of the other's existence.
The story begins when 15-year-old Nanoka moves to Tokyo to live with her father and brother, the latter being 27 years old and employed by a marriage-arranging company. Koshiro first encounters Nanoka on the train one morning, and returns her dropped train pass. Despite their age difference, they feel a brief spark of connection before they go their separate ways.
Soon after that, they encounter each other once again near an amusement park, where they go on an impromptu date. While riding the Ferris wheel, the two open their hearts to each other and discuss their recent romantic woes. Nanoka comforts Koshiro when he breaks down and cries, and he realizes that he is very attracted to her. Right after the date, they meet their father, and are startled to realize they are siblings.
Koi Kaze is about Koshiro's love for Nanoka, his conflicting drive to obey societal norms, and Nanoka's growth into womanhood and her growing feelings for her brother.
The Koi Kaze anime was released on three DVDs in the USA. The first volume, "The Reunion", deals with the two siblings learning to live with each other, Koshiro trying to suppress his attraction to his sister, and Nanoka awakening as a young woman while developing an attachment to her brother. The story is continued in "Budding Attraction", where the two come to realise their true feelings for each other. The final volume, "The Decision", concludes the story as Koshiro chooses to move out and sever his ties with his family, until his sister finds and confronts him.
- At 27, Koshiro is a great bear of a man with a rarely-shaven beard, who works for a marriage-arranging company. Though he initially comes off as an insular, gruff man verging on unintentional boorishness, it is more accurate to say that he is someone who feels subtle and powerful emotions, but lacks the eloquence to express them. His natural protectiveness of Nanoka wars with his strong attraction to her and his sexual frustration since his breakup, and he is often brusque with her as a result.
- She is 15 years old when the series begins, Nanoka is a bright and active girl, largely typical of her age group. She is attached to her newly-rediscovered older brother, and is easily annoyed with his brusqueness. Her friends periodically tease her about having a "brother complex", which has more truth than she's willing to admit to anyone besides herself. Ironically, she comes to terms with her feelings for her brother before he does.
- Koshiro and Nanoka's father. While he was married to Makie, he had an affair; it is implied that this was the cause of their divorce. A man in late middle age, he is prone to bouts of hysterical worry, and is somewhat clueless. Still, he cares for his children (although he clearly favors Nanoka) and does his best to make Nanoka feel at home in her new surroundings. He is an architect.
- Koshiro and Nanoka's mother, and Zenzo's ex-wife. Living in a town an hour away by train, Makie runs a hair salon. She is a direct, motherly woman who thinks little of her former spouse. Like him, she favors Nanoka slightly over Koshiro.
- Koshiro's ex-girlfriend, Shoko is an office lady who hates her job. She broke things off with Koshiro just prior to the series' start, claiming that she had fallen for someone else. She said that she found Koshiro cold, and asked whether he ever loved someone from the bottom of his heart. When she runs into Koshiro later, the evening they spend at a restaurant raises even more questions about how she regards him.
- Koshiro's supervisor at the marriage-arranging company, Kaname is about the same age as he. While she is often critical of his sloppy appearance, she encourages him where she can. She is among the first to note the strange tension between Koshiro and Nanoka. It is occasionally hinted that she may be attracted to Koshiro.
- One of Koshiro's coworkers, the nerdy Kei is a complete lolicon pervert, constantly trying to meet high school-age girls. After he finds out about Nanoka, he is constantly after Koshiro to set the two of them up. &
- Nanoka's friends from school. Futaba, the bespectacled and pigtailed one, is frenetic and a rumormonger, but not unthoughtful, and is the closer of the two to Nanoka. Tamaki, the cooler and more worldly of the two, tends to serve as a counterpoint to Futaba.
- A popular and attractive boy in Nanoka's class. He's initially introduced as a possible rival for her affections, but in the manga he has a forbidden love of his own and is infatuated with the school librarian. Unlike Futaba or Tamaki, Miyauchi does not tease Nanoka about her "brother complex" and tells her not to take their joking to heart.
- Opening theme: "Koi Kaze" by éf (episodes 1-11 and 13; episode 12 has no opening animation, picking up immediately from the end of episode 11)
- Closing theme: "Futari Dakara" by Masumi Itō (all episodes; closing animation changes from episode 10 onward)
- All BGM composed by Takumi Masanori and Makoto Yoshimori