What is Touhou?

The Touhou Project (東方Project), also 東方プロジェクト (Touhou Purojekuto) or Project Shrine Maiden, is a Japanese doujin game series that specialises in shoot 'em ups by sole Team Shanghai Alice member ZUN. Generally, it's a series of 2D (with 3D background) vertically-scrolling danmaku shooting games, that also creates related print works and music CDs. There are also seven spinoffs co-produced with Twilight Frontier, called "danmaku action games." The works of Touhou Project are sometimes called the Touhou Series (東方シリーズ Tōhō shirīzu) for convenience.

~ touhouwiki.net