The term "doujin soft", also known as "doujin games", refers to a sub-genre of doujinshi — essentially, self-published video games. They are also Japan's equivalent to an Indie Game.
Doujin softs are generally released to Windows-based computers, and, like doujinshi, doujin softs may offer games based on one or more intellectual properties, or entirely original works. The most frequent genres [...] [tvtropes.org]