Doujinshi is an amateur fan made and self-published work, such as comics, novels especially of mangas.
It usually features casts and plots of other already existing animes, mangas or video games in some instances.
There are various sorts of “doujinshis”, but most of the time it is in a form or erotic manga.
Because they are amateur publications, “doujinshis” are pretty cheap and they can be found on Ebay, jpqueen.com and on other sites.
The literal meaning of the term is complex. It contains Japanese words like “doujin” which roughly means “club” or a group of people who share the same interests, and “shi” means “magazine”.
“Doujinshis’ have been around for a long time.
Anime and manga fans and/or creators have been buying and selling them, for example in a very famous fair in Japan, named Comic Market where “doujinshis” have been sold since the 1970s.
In Japan, these fan-created mangas have an active culture and it expanded to the West as well.
In the 1980s it got more popular for fans to self-publish their “doujinshis” on existing anime, manga characters or series they love and enjoy.
“Doujinshi” carries a common misunderstanding with it, that it is a story featuring already existing famous anime characters in a male same-sex relationship with each other, targeting a female audience.
However, it has to be noted that in many cases “doujinshis” are pornographic and erotic stories, but it is far from all subgenres.
Many share their own publications on different kinds of social media, such as Wattpad, Reddit or Tumblr.
Also, in Japan it has such an active cultivation that people hold conventions especially for “doujinshis”, such as Comiket, which is the biggest Japanese “doujinshi” convention.