Koi Kaze, Ore no Imouto ga Konnani Kawaii Wake ga Nai. Specials Recommendations
In both series, the main protagonist has a particular relationship with his little sister. The protagonists struggle with their feelings throughout the series, as it is no easy topic.
Although Koi Kaze has more of a mature, drama-filled atmosphere, both anime are thought-provoking and have the courage to approach one of the modern world's remaining taboos in their own way.
These two series are definitely recommended to all those who are not afraid or wish to learn more about incest in modern society.
Koi Kaze is like the Intellectual and Elite version of Ore no Imouto, which it certainly influenced. However Chidori is a vastly superior version of Manami, and in Koi Kaze the main characters actually have guts to stand by their feelings even without having a firm plan to solve the inevitable problems. The realistic and dramatic portrayal is much in line with reality, as opposed to the Harem Esque and more mainstream OreImo. While Koi isn't as pleasing as OreImo visually (unless you are fond of the Unparalleled NHK), it tackles the Elephant in the room exponentially better.