Also known as: HEN, 変
May refer to either of a pair of related (shared universe) adult-themed seinen romance manga composed by Oku Hiroya of Gantz fame, both serialized in Shuukan Young Jump; the first - 変 (translated: Strange) - beginning in 1988 running thirteen volumes until 1992, and the second - HEN (Strange, as written in rōmaji) - which immediately followed and enjoyed an eight volume run. The second serialization was the basis of HEN, a 1997 two-volume OVA going under the English title Strange Love. A live action television series covering both works preceded the OVA by a year.
Note that the manga's simple kanji title will significantly dilute searches for relevant works on Pixiv.