Koi Kaze follows the eyes of Saeki Kōshirō, a 27-year-old marriage consultant as his life takes an interesting turn with the addition of Kohinata Nanoka, his high school sister that he had forgotten about, lives with him under the consensus of their father. Their intertwined life creates a struggle rarely seen in today’s anime, for such a struggle has nearly turned into one for either a comedic effect or a standard trope.
Clearly, the overall theme in this story is the boundaries in the relationship between brother and sister. Kōshirō is conflicted with his own moral standards and the society that he is in. He knows Nanoka is his sister, but cannot help but feel something different than a normal brother-sister relationship. It also does not help that he had once masturbated with his sister in mind, of which he gets angry about moments later due to said inner conflict. From on outsider’s point of view, their relationship seems awkward at best, not because the siblings are in love with each other, but of Kōshirō’s inability to figure out how to live with a younger sister, as such a thing is not something that he was accustomed with. Nevertheless, Kōshirō attempts to become the best older brother he can be, given the boundaries of society.
His own conflicting feelings is only augmented by Nanoka’s own feelings for him, one that is also more than a brother-sister relationship. Falling in love at first sight, Nanoka’s growing feelings began when she first met her brother, who did not know they were related at first. While she was lost wandering around the city, Kōshirō took the time to spend time with Nanoka until it was time for her to go on her way. Ironically, Nanoka knew that he was her brother, which made it all the more awkward when Kōshirō finds out about their relationship through their father. Unlike the older and more knowledgeable about society’s qualms brother, Nanoka is more pure, genuinely falling for her brother under the trust that she put on him, that he would always be with her after not seeing her for so long and protecting her. While aware that such feelings are not appreciated given the world around them, Nanoka cannot let go of it, no matter how many times she is reminded of it.
The climax of the story happens when Kōshirō decides to move out and live by himself, of which he was successful in finding an apartment complex. This is due to his still conflicting emotions, believing that staying away from his sister would allow him to return to the time when it was just him and his father. However, in this scenario, distance was what made them even closer. The time Nanoka has spent with her brother were the most important of her life. For that, she decides to find him and ultimately stay with him there. Between the two’s emotional state was Chidori Kaname, a supervisor of Kōshirō who can be seen as a representation of the norms of society. Despite trying her best to get the two to realize that their relationship is wrong and performing actions to prevent the two from developing further feelings, this ultimately came for the naught as the two realized they cannot live without each other.
The final push against the boundary was when Nanoka asked Kōshirō if Kaname was his girlfriend. Had Kōshirō said “Yes,” Nanoka would have ended her pursuit for Kōshirō, and Kōshirō would have been able to hold firm the views of his society. However, Kōshirō answered “No,” which brings the two closer than ever before, eloping for that night. Such actions mean that they have fully accepted each other and are willing to risk the dangers of going against the norm if it meant not living with each other. And so, they have accepted each other’s feelings. Their journey after their decision will be a difficult one, but as long as they were together, they will find a way to continue living to the fullest.
Say what you will about the theme of the story, but I believe Koi Kaze is a touching story for many to see. I would recommend this show for anyone. If such a topic bothers you, you need not watch it, but for those who are indifferent, I would like you to see it and, if you would like, judge whether or not the decisions made by the two siblings were correct and what you would have done had you’d been in their shoes.