Dōjin (同人 dōjin?), often romanized as doujin, is a general Japanese term for a group of people or friends who share an interest, activity, hobbies, or achievement. The word is sometimes translated into English as clique, fandom, coterie, society, or circle (e.g., a "sewing circle").
In Japan, the term is used to refer to amateur self-published works, including manga, novels, fan guides, art collections, music and video games. Some professional artists participate as a way to publish material outside the regular publishing industry.
Annual research by the research agency Media Create indicated that of the $1.65 billion of the Otaku industry in 2007, doujin sales made up 48% ($792 million).
Literary circles first appeared in the Meiji period when groups of like-minded waka writers, poets and novelists met and published literary magazines (many of which are still publishing today). Many modern writers in Japan came from these literary circles. One famous example is Ozaki Koyo, who led the Kenyusha society of literary writers that first published collected works in magazine form in 1885.
After World War II manga dōjin started to appear in Japan. Manga artists like Shotaro Ishinomori (Kamen Rider, Cyborg 009) and Fujio Fujiko (Doraemon) formed dōjin groups such as Fujiko's New Manga Party (新漫画党 Shin Manga-to?). At this time dōjin groups were used by artists to make a professional debut. This changed in the coming decades with dōjin groups forming as school clubs and the like. This culminated in 1975 with the Comiket in Tokyo.