Bounded Field

Bounded Field first schema (Japanese).png|Bounded Field with effect exerted on the boundary line.
Bounded Field second schema (Japanese).png|Bounded Field with effect exerted on the interior.
A is a geographical form of magecraft whereby one knits a boundary line of magical energy around a space to separate its inside from the outside, cutting off and isolating that space from the outside worldKara no Kyoukai Volume 4: Void Shrine (「　　」) - 2Fate/stay night - Prologue: Day 3Mahoutsukai no Yoru - Chapter 4: "Her Name Is Blue" and then imposing an effect on the inside (or the boundary line itself). It is primarily used to protect one's body or property.
==Mechanics==
The Japanese term for "Bounded Field" originates from Buddhism.Lord El-Melloi II Case Files Volume 1: case. Adra Castle Separation - Chapter 1 Part 1 The concept that repels people is something much more basic than magecraft, a fundamental function of the human brain, so magecraft is not needed for a place to naturally repel people without the need for external, mysterious powers. Bounded Fields are always something that isolates an area from the outside world, but it has come to represent techniques by which a magus protects their body.
Two types of Bounded Fields exist. The first applies a process on terrain, buildings, etc. to create a boundary between inside and outside. The second involves encircling a prepared component and then cutting the space off. The former includes wards that are used to protect a magus’ mansion or land, designed as defensive measures against other magi, or security measures. The latter would include uses such as the encircling of a specific ground area using rope woven from hair imbued with magical energy, the drawing of magic circles, and so forth.
Invisibleair.jpg|Artoria Pendragon's Bounded Field Invisible Air.
Invisible Air (ufotable).jpg|Invisible Air (ufotable).
Blood Fort Andromeda.png|Medusa's Noble Phantasm, the Bounded Field Blood Fort Andromeda.
Ryuudou Temple being surrounded by Caster's Bounded Field.jpg|Medea's Bounded Field at Ryuudou Temple.
Caster's Bridge Bounded Field.jpg|Medea's Bounded Field on the Fuyuki Bridge.
Wodime Bounded Field.png|A Bounded Field created by Kirschtaria Wodime.
There are various kinds of Bounded Field of different levels, as infinite different effects are possible within a Bounded Field. There are ones that conceal the area from people's eyes, be it by creating a physical wall, an invisible barrier, or something less tangible that uses mirrors, mist, or trees to conceal. There are also those that limit the use of magecraft within them, but most aggressive of all are those that oppress lifeforms within them. The ideal Bounded Field is one that is both undetectable and impervious to interference from the outside, hence why the highest-ranking Bounded Fields are a form of subliminal coercion that makes passers-by completely unable to notice them or even notice that anything is wrong. A Bounded Field that just mimics another world and makes people realize that something is wrong is the worst of the worst and seen as the mark of a third-rate magus.
Once constructed, the established boundary line will delimit the range of the powers of the Bounded Field, but it is possible to engrave magic sigils across the interior of the field to expand the area of effect and strengthen it. Removal of the sigils by a third party is possible as long as the technique used to engrave them isn’t too advanced. In this case, it is only possible to temporarily hinder the Bounded Field by dissipating the magical energy used to activate it, but the creator of the Bounded Field can amend this by simply putting more magical energy back into it. In the Fate/stay night anime this was changed to the sigils being easily destroyed. However, new sigils are constructed by the actions of the old ones, making the Bounded Field capable of self-repair in due time.
As their original purpose was for the creation of safe havens, the effects that can be set within a Bounded Field are in their majority those whose aim is to protect the caster. Offensive variants do exist, but as they work through indirect magical interference, their efficiency against those who can protect themselves magically is low.
RokudouKyoukaiActivation.gif|The mobile Bounded Field .
RokudouKyoukaiBinding.gif
Threefold Barrier.png| in Fate/Grand Order, illustrated by Takahashi Takuro.
As Bounded Fields is a magecraft imposed on a chosen area, it should not be possible to move such fields once set, but those created by Souren Araya and Sancraid Phahn are exceptions to this rule.
Medea's advanced skill in magecraft allows her to construct an "another world" that is on the same scale as a Reality Marble, though the time to prepare such a thing is extreme. It is shown in the Fate/stay night [Unlimited Blade Works] anime as a simple re-creation of the Fuyuki Bridge, with a foggy interior.Fate/stay night [Unlimited Blade Works] - Episode 12: "The Final Decision" She used the lingering traces of the previous war's Caster's summoned Horrors to create it. Medea also shows that with more time and effort something similar to "another world" can be constructed, which she refers to as being a sort of Reality Marble, where she has prepared her own city. Medea even claims the doll-people inside are "literally" alive, because she takes the time to make each and every one by hand.Fate/Grand Order - Medea's Interlude: Witch's Backyard It is said that Medea displaying the ability to build elaborate miniature worlds, the "most basic and most advanced principle of magecraft," is proof that she learned directly from Hecate.Fate/Grand Order material II - Medea, translated by ComunCoutinho on Reddit
Pale Rider's first Noble Phantasm Doomsday Come creates a Bounded World that takes the form of a pseudo-Underworld with the Master as its origin point.
Dead Apostles who know magecraft make layers of Bounded Fields to form when creating their lairs. This invisible protection is similar to the ones that hide away the world of the fairies, which fool even nature itself. The lair is accessible only by those who are invited in, and they are difficult to invade, taking even the trained magi of the Mage's Association several years to find one. These lairs are enshrouded by darkness, by shadows, by longing for rationally, and by fear towards the taboo, so they cannot be found by humans.Prelude I 
The most powerful type of Bounded Field, known as Reality Marble, makes the space itself act as a boundary line. It is the closest magecraft to real Magics, a taboo among taboos, Mystery among Mysteries and one of the pinnacles for magi, so researches on it have been banned by the Mage's Association.
==Examples of Bounded Fields==
*Touko Aozaki's Bounded Field.
*Emiya residence Bounded Field.
*Dead Apostle Territorial Fields.
*Avalon
*Blood Fort Andromeda
*Breaker Gorgon
*Hounouden Rokujyuyonshou
*Invisible Air
*Kibisis
*Rho Aias
*Rokudou Kyoukai
*Ryuudou Temple’s Barrier
*Kayneth El-Melloi Archibald’s twenty-four-layer Bounded Field protecting his hotel floor.
*Sancraid Phahn's personal Bounded Field that moves with him.
*The Mist
*Crystal Palace
*Ragnarök Lífþrasir
*Akhilleus Kosmos
*Ganesha Vighneshvara
*Doomsday Come
*The "Garden."
*Medea's "Other World."
*Cathedral
*Vampire-containing Bounded Fields used by the Holy Church.
==References==
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vi:Kết Giới
Category:Magecraft
Category:Terminology in Tsukihime
Category:Terminology in Fate/stay night
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