A Specialized Bounded Field (固有結界 Koyuu Kekkai, lit. Spiritual Barrier) is an extremely rare high-class sorcery that expands an enclosed alternate reality. Within a Specialized Bounded Field, users are able to violate the laws of nature, the creation of an ideal battlefield. According to Shuu Amami, this technique is considered as forbidden.
The concept of Specialized Bounded Field in 11eyes and its predecessor 3days is a different concept from Type-Moon. Although Specialized Bounded Field in 11eyes and 3days also enclosed an alternate reality where the laws of nature can be violated, the biggest difference between the two is that the Specialized Bounded Field of Type-Moon is representative of the caster's soul and so the caster is not able to pick the type of violation desired, whereas in 11eyes and 3days, the effect of the Specialized Bounded Field can be chosen as the spellcaster creates it.
Walter's Specialized Bounded Field is a yellow-and-red-horizon-like world with hovering rocks, with the Necronomicron as its core and supported by the magical power of the Emerald Fragment. Inside this space, the only magical element that is active is Larvae, the other elements are very limited inside the barrier, putting non dark art users at a great disadvantage. Walter can summon the Larvae to support him or use them as a source of power. He constructed this Specialized Bounded Field inside another barrier, but it is unknown whether because it was the uniqueness of this Specialized Bounded Field that made it possible or because of Walter's skill. Unlike Lieselotte's Red Night or Kanae's mirror world, this Specialized Bounded Field integrity was weak, as Ryouichi Kusakabe was able to rip it apart with a spell.
Lieselotte's Specialized Bounded Field is called Phantasmagoria (幻燈結界 Fantazumagoria). Its weakest level only creates illusions which fools the eyes; however, as more magical power is utilized, the illusions become stronger, more convincing and at its strongest level, they become reality itself. The Specialized Bounded Field's most powerful state is portrayed as a Larvae flooded crimson dimension–dubbed as the Red Night. The purpose of this dimension is to provide the VoidStone inside Lieselotte's body with enough dark magical power to execute her ultimate spell: Hell Fall. It should be noted that despite being the same kind, Lieselotte's Specialized Bounded Field is significantly more powerful than Walter's. While Walter's Specialized Bounded Field can only call forth ghost-like Larvae, the Larvae inside Red Night takes on specific forms and can even evolve to increase their power. So far, the strongest form of the Larvae shown is the humanoid form. In addition, another striking difference is that Lieselotte's Specialized Bounded Field does not restrict other elements because Shiori Momono and the Black Knights could still perform non-Larva-based spell inside the Red Night whereas Miyu Hiiragi has to rip off part of herself, which consists of the four elements, to perform non-Larva-based spell inside Walter's Specialized Bounded Field.
Kanae possesses a unique Specialized Bounded Field which is completely different from both Walter's and Lieselotte's. While the other two's Specialized Bounded Fields strengthen their users with the power of the Larvae, Kanae's Specialized Bounded Field is a green mirror world called Mirror Maze (鏡界 Miraru Meizu). As the name implies, through the Artificial Emerald Tablet, this Specialized Bounded Field tunes magical power into itself so that normal magi cannot obtain magical power through their magical circuits inside it. Since the Artificial Emerald Tablet was created with the Od, or life energy of people with a certain genetic trait, Shuu Amami figured out that he can access his magical circuits using people with such genetic trait as a medium.