Dōjinshi (同人誌; Dōjinshi, 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; dōjin, 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 circle (サークル, sākuru). A number of such groups actually consist of a single artist: they are sometimes called kojin circles (個人サークル; personal circles).
Dōjinshi are made by artists or writers who prefer to publish their own materials. Avid fans of dōjinshi attend regular dōjinshi conventions, the largest of which is called Comiket (short for "Comic Market") held in the summer and winter in Tokyo's Big Sight. At the Convention, over 20 acres (81,000 m2) of dōjinshi are bought, sold, and traded by attendees. Dōjinshi creators who based their materials on other creators' works normally publish in small numbers to maintain a low profile from litigation. This makes a talented creator's or circle's dōjinshi a coveted commodity as only the fast or the lucky will be able to get them before they sell out.
Over the last decade, the practice of creating dōjinshi has expanded significantly, attracting thousands of creators and fans alike. Advances in personal publishing technology have also fueled this expansion by making it easier for dōjinshi creators to write, draw, promote, publish, and distribute their works. For example, some dōjinshi are now published on digital media. Furthermore, many dōjinshi creators are moving to online download and print-on-demand services, while others are beginning to distribute their works through American channels such as anime shop websites and specialized online direct distribution sites.
During the 1980s, the content of dōjinshi shifted from being predominantly original content to being mostly parodies of existing series.
The practice of doujinshi can be beneficial to the commercial manga market by creating an avenue for aspiring mangaka to practice, and talented doujinshi creators are contacted by publishers. This practice has existed since the 1980s.
In 2008, a white paper on the otaku industry was published, this estimated that gross revenue from sales of doujinshi in 2007 were 277.3 billion yen, or 14.9% of total otaku expenditure on their hobby.