What is doujinshi?

Answer 1

Dōjinshi (同人誌?, often transliterated as doujinshi) are self-published Japanese works, usually manga or novels. They are often the work of amateurs, though some professional artists participate as a way to publish material outside the regular industry. The term dōjinshi is derived from dōjin (同人?, literally "same person", used to refer to a person or persons with whom one shares a common goal or interest) and shi (誌?, a contraction of zasshi, meaning "magazine"). Dōjinshi are part of a wider category of dōjin including, but not limited to, art collections, anime, hentai and games. Groups of dōjinshi artists refer to themselves as a sākuru (サークル?, circle). A number of such groups actually consist of a single artist: they are sometimes called kojin sākuru (個人サークル?, personal circles).

Thank you wikipedia :D