An 18+ visual novel made during TYPE-MOON's doujin days. Tsukihime is one of the most successful doujinshi work of its time, and stands alongside Higurashi no Naku Koro ni and Touhou Project as one of the "three miracles" of doujinshi (here doujinshi refers to non-commercialized or self-published work, as opposed to derivative of other works).
After several trial releases, the full version of Tsukihime was released in December 2000 during the winter Comiket. The game captured its audience through the story's numerous twists and drama, the large number of likable female casts, as well as the rich world and music. In January 2001, a fan disc called PLUS-DISC was also released. Due to the original game's popularity, TYPE-MOON released a fan disc in August of 2001 called Kagetsu Tohya to further flesh out the game world's setting. In 2003, an anime adaptation titled Shingetsutan Tsukihime began airing. The quality of the anime was deemed to be extremely poor, however, and was overall considered to be a failure. When TYPE-MOON transitioned into a commercial company in 2003, it packaged the original game, Kagetsu Tohya, and PLUS-DISC into a bundle called Tsuki-Bako, and released the collection to signal of the end of TYPE-MOON as a doujinshi group.
Tsukihime's success helped cement TYPE-MOON's popularity among fans and gave the group the resource it needed to become a company and develop Fate/stay night. Currently, copies of the game and its fan discs are almost impossible to find, and are usually found on auction websites for extremely high prices.
In April 2008, TYPE-MOON announced a remake of Tsukihime, featuring new artwork and a new Satsuki route. Little information on the remake has been release since.
The story of Tsukihime revolves around Tohno Shiki, a young man who is able to see "lines of death" (formally known as the Mystic Eyes of Death Perception) after a childhood accident. As a result, Shiki is able to kill anything by tracing its "death line." Of course, seeing death everyday usually drives people mad, and Shiki is no exception. Luckily, no sooner has Shiki received his power when he receives a pair of glasses from the magician Aozaki Aoko that can supress the power of his eyes, allowing him to live a normal live.
Fast forward many years, after living away from the Tohno household for many years, Shiki returns after the death of the head of the Tohno family. Back home, he meets his sister Akiha, who is now the new head of the Tohno household. Later Shiki meets Arcueid, a vampire princess, and accidentally kills her. Thankfully Arcueid revives herself and enlists Shiki in her quest hunting down the bad guys to make up for "killing her." The bad guy in this case is Roa, a vampire that reincarnates himself each time he is killed by Arcueid. Also joining the Roa-hunting fray is Ciel, an assassin from the Church who is immortal thanks to previously being possessed by Roa. Add Akiha's two maids, Kohaku and Hisui, to the story, and we have a complicated love/suspense/supernatural story that spans 5 routes and contains multiple endings.
In Kagetsu Tohya, which takes place a year after the events in Tsukihime, Shiki finds himself stuck in an infinite loop of dreams. Eventually Shiki finds the cause of all this, Arcueid's familiar Len (sometimes referred to as Ren), and gets himself out of the dream world.