In this context, etchi should be understood as sexually forward and is synonymous to iyarashii ( 嫌らしい, dirty or disgusting) or sukebe ( すけべ, a person with sex on the brain).
In 1952, the magazine Shukan Asahi reported that a woman who was groped by a stranger in a movie theater reacted with "ara etchi yo" ( "hey, that's perverse"). Īfter the Second World War, in the 1950s, interest in hentai was renewed, and people would sometimes refer to it just by the first English letter, H (pronounced as エッチ, / eɪ tʃ/). In the 1930s, censorship became more common leading to fewer books being published on this theme.
Matsuzawa calls it a period characterized by a " hentai boom". In the 1920s, many publications dealt with deviant sexual desires and the Ero Guro Nansensu movement. In the 1910s, it was used in sexology in the compound expression "hentai seiyoku" ( 変態性欲, abnormal sexual desire, which is rephrased as " sexual perversion" in modern times) and became popular within the theory of sexual deviance ( Hentai seiyoku ron), published by Eiji Habuto and Jun'ichirō Sawada in 1915. Slowly, the meaning expanded until it had the meaning of non-standard. In this context, it was used to refer to disorders such as hysteria or to describe paranormal phenomena like hypnosis or telepathy. Hentai was introduced in the Meiji period as a term for change of form or transformation in science and psychology. In the word hentai (変態), the first kanji hen refers to strangeness or weird, and the second kanji tai refers to a condition or state. However, it is typically written as "ecchi" in the Western world. The correct transcription of the word エッチ in Hepburn notation is "etchi".