"Boundary of Emptiness") sometimes referred to as Rakkyo (らっきょ), is a Japanese light novel series, written by Kinoko Nasu and illustrated by Takashi Takeuchi.

A manga adaptation illustrated by Sphere Tenku started serialization in September 2010 in Seikaisha's online magazine Saizensen.

Set in Japan predominantly during the late 1990s, The Garden of Sinners follows the story of Shiki Ryougi (両儀式, Ryōgi Shiki), a teenage girl raised as a demon hunter who acquired the "Mystic Eyes of Death Perception" after surviving a fatal accident.

It also chronicles Mikiya Kokutou's unwavering efforts to get closer to her when they were still high school students and their adventures later on in dealing with supernatural cases as investigators for Touko Aozaki's detective agency, Garan no Dou.

This is set in an alternate universe to Tsukihime and Fate/stay night; in which it serves as the prototype for both series as well as introducing many of the concepts prevalent within the latter two.

[citation needed] The series deals with the paranormal and tackles mature topics such as suicide, rape, patricide, incest and murder.

A manga adaptation of the novel series written and illustrated by Tenkuu Sphere is currently being serialized in Saizensen web magazine since September 15, 2010.

On August 9, 2002, a drama CD written by Ōmori Rice (大森ごはん) based on the Overlooking View chapter was released.

The first chapter, titled Overlooking View (俯瞰風景, Fukan Fūkei), premiered across Japanese theaters on December 1, 2007, with the second, third, fourth, fifth, sixth, and seventh chapters, Murder Speculation – Part 1 (殺人考察(前), Satsujin Kōsatsu (Zen)), Remaining Sense of Pain (痛覚残留, Tsūkaku Zanryū), The Hollow Shrine (伽藍の洞, Garan no Dō), Paradox Spiral (矛盾螺旋, Mujun Rasen), Oblivion Recording (忘却録音, Bōkyaku Rokuon), Murder Speculation – Part 2 (殺人考察(後), Satsujin Kōsatsu (Go)) being released soon after on December 29, 2007, followed by January 26, 2008, May 24, 2008, August 16, 2008, December 20, 2008, and August 8, 2009, respectively.

[16] 3D conversion of The Garden of Sinners first movie called Overlooking View 3D (空の境界 俯瞰風景 3D, Kara no Kyōkai: Fukan Fuukei 3D) was released in July 2013.

An eighth film, Future Gospel (空の境界 未来福音, Kara no Kyōkai: Mirai Fukuin), was released in September 2013 and had grossed US$1,710,413 by October 20.