1993 July 25, Curtis H. Hoffmann, “Dr. Etchi's Guide to 'H' Manga”, in rec.arts.manga[1] (Usenet), retrieved 2023-03-15:
In Japan, 'hentai' means 'pervert,' so the sex-related manga are called 'H' manga, which is rendered into katakana as 'etchi' or 'ecchi'.
1998 January 7, Michael Derek Ho <mikeho@umich.edu>, “FS: H Doujin”, in rec.arts.anime.marketplace[2] (Usenet), retrieved 2023-03-15:
All prices include shipping. All doujin are H.
2013 November 25, [anonymous], “/a/ - Anime & Manga » Thread #97331992”, in Desuarchive [originally posted on 4chan][3], Bibliotheca Anonoma, retrieved 2023-03-15, [post #97334217]:
>most H-scene in the game / Developer's favorite girl confirmed.
