Like their mainstream counterparts, doujinshi are published in a variety of genres and types. However, due to the target audience, certain themes are more prevalent, and there are a few major division points by which the publications can be classified. It can be broadly divided into original works and aniparo—works which parody existing anime and manga franchises.
As in fanfics, a very popular theme to explore is non-canonical pairings of characters in a given show (for doujinshi based on mainstream publications). Many such publications contain yaoi or yuri (that is, homosexual) motives, either as a part of non-canon pairings, or as a more direct statement of what can be hinted by the main show.
A major part of doujinshi, whether based on mainstream publications or original, contains sexually explicit material, due to both the large demand for such publications and absence of restrictions official publishing houses have to follow. Indeed, often the main point of a given doujinshi is to present an explicit version of a popular show’s characters. Such works may be known to English speakers as “H-dōjinshi”, in line with the former Japanese use of letter H to denote erotic material. The Japanese usage, however, has since moved towards the word ero, and so ero manga is the term almost exclusively used to mark doujinshi with adult themes. Sometimes they will also be termed “for adults” or 18-kin. To differentiate, ippan is the term used for publications absent of such content.