doujin computer game series created by Team Shanghai Alice

Touhou or Touhou Project (Japanese: 東方Project, Hepburn version: Tōhō Purojekuto) is a series of space shooter bullet hell games developed by a single individual game developer Team Shanghai Alice. From the year 1995, the team leader, Jun'ya Ota, also and mainly known as ZUN, has made code, art, writing and music for the series, publishing 18 main series games and five spin-offs as of May 2021. He has also written manga print works and composed albums, and worked together with the developer Twilight Frontier on six Touhou fighting games.

The games are set in Gensokyo, a place sealed from the outside world where mostly humans and youkai live. Youkai are creatures from Japanese folklore that are represented as people in the game as female characters most of the time. Reimu Hakurei, the shrine maiden of the Hakurei Shrine and the main character of the series, is often involved in settling supernatural incidents in and around Gensokyo. Other main characters include Marisa Kirisame, a witch, Sakuya Izayoi, a maid, Reisen Udongein Inaba, a moon rabbit, and Sanae Kochiya, a shrine maiden at the competing Moriya Shrine.

The first five games were developed for the Japanese NEC PC-9800 computer series, the first one, Highly Responsive to Prayers, was released in August 1997. The series' famous danmaku system was introduced in the second game, Story Of Eastern Wonderland, also in 1997. The release of Embodiment of Scarlet Devil was a change to Microsoft Windows. More sequels followed, including some spin-offs that were different from the normal bullet hell format.

This game series has been very famous for being a large source of doujin content as different types of media such as songs, artworks, games and stories have been made by the followers of Touhou Project, and as a result it has gained a very large following outside Japan, due to the small amount of rules regarding copyright set up by ZUN. These works are usually sold at Fan conventions such as Comiket, which is notable for highest doujin circle participation, and the official Reitaisai, where early versions of upcoming games are put on display there.