Based on

Movies like Youth Experience (1981)

An underground gay video already existed in the late 1970s in japan. "Seishun taiken shirīzu shōnen Jun no natsu" is the oldest ever know sold through legitimate channels however, it turned out that the Athens Ueno store was producing 8mm film works since 1973. So far, it has not been confirmed that Athens' original work was sold on VHS/Beta before Shonen Jun no Natsu. As a side note, the first domestically produced adult video for straight men was also released in the same year, and it is no exaggeration to say that these works for adults greatly contributed to the spread of VHS decks in Japan throughout the 1980s.