"dōjinshi" printers are companies that specialize in professional printing and binding of the self-published magazines called "dōjinshi". "dōjinshi" are a popular medium of self-publishing in japan, mostly for fan-made manga. "dōjinshi" printers print not only "dōjinshi", but also fan-made merchandise such as stationary, stickers, posters and mugs. the companies are also involved in the organization of "dōjinshi" conventions, and play a role in establishing and enforcing content regulations for "dōjinshi". over a hundred "dōjinshi" printers are active in japan today.