Great Hakurei Barrier
Great Hakurei Barrier
The Great Hakurei Barrier (博麗大結界 Hakurei Dai-Kekkai) is the barrier that hides Gensokyo away from the Outside World, and which allows youkai to survive within even when outside humans no longer believe in them. It is known that the Hakurei Shrine is located on the border and believed that Yukari Yakumo lives somewhere along the border as well (though not near the shrine).
Some time in the 15th century, the youkai now known as Yukari Yakumo set the groundwork for the barrier with her "Youkai Expansion Plan", turning Gensokyo into a haven for youkai by enchanting it to attract the fantastic and repel the mundane.
The Barrier proper was a proposal of the Sages of Gensokyo (a group including Yukari), which would be erected by humans in Meiji 18 (CE 1885) and later reinforced by youkai. While the idea was at first highly controversial among youkai, and led to much infighting between them, it is now almost universally accepted. Although Yukari is widely acknowledged as the barrier's "creator", Yuyuko Saigyouji doubts that even she could create a barrier of this level by herself.
The barrier is so important to Gensokyo, that the year of its formation is now marked as the year 0 for Gensokyo Calendar.
The Hakurei Shrine, which exists on both sides of the border, is supposed to be its only gateway. However, the phenomenon of "spiriting away" can also cause objects and even living beings to slip through the border at random, particularly if they have started to be forgotten by the outside world. For instance the crested ibis started to become more common in Gensokyo after the Japanese variety were recognised as extinct, and paper started showing up more frequently with the rise of digital storage. Outside humans are not protected by the Spell Card rules and thus can be freely preyed on by youkai, but they may choose to become citizens of the Human Village or request for the Hakurei shrine maiden to send them home.
Even in modern times, it is still possible for youkai, gods and even entire locations (such as the Ruined Western Mansion, Scarlet Devil Mansion and Moriya Shrine) to pass through the border and enter Gensokyo.
While some youkai (most notably Yukari Yakumo, Nue Houjuu and the zashiki-warashi) have shown the ability to exit Gensokyo and travel to the outside world, it appears that this requires uncommon knowledge, abilities and/or conditions, as other characters seem to think of it as nigh-impossible. It is believed that youkai go on "hunting trips" through the border to gather humans from the outside world as food, disguising the kidnappings as stories of people running away from home, but it is unclear how and when these are performed.
As a "boundary of common sense" the barrier is designed to affect only living things and their creations, while allowing natural forces to pass through (hence the barrier is permeable to sunlight, and Gensokyo's rivers are connected to those of the Outside World). The space on the edges of the barrier is non-Euclidean - humans who attempt to leave the barrier will find themselves encountering the same landmarks over and over, without ever getting any further from where they started.
Urban Legend in Limbo describes two ways of travelling through the Barrier. True, complete passage can be achieved by punching a hole in the barrier and walking through. However, beings may also enter or leave Gensokyo by being "spirited away" - most such travellers have little physical presence (sometimes to the point of appearing only as a shadow) and will eventually be pulled back home, remembering their trip as if it were only a dream. In fact at least some of these trips have taken the form of literal dreams, with the traveller's mind returning to their body when they awake. It is possible for a dreamer in the Outside World to bring back objects from Gensokyo in this manner.
The barrier is weaker around objects which carry the spiritual energy of the Outside World. Usually this effect is barely noticable, outside of concentrated sources like the Occult Balls. However, when one of the trees around the Hakurei Shrine was killed, a tree from the Outside World was drawn in to replace it, causing the surrounding area to become distorted. On another occasion Rinnosuke Morichika was briefly drawn into the Outside World due to concentrating on an MP3 player while Reimu was nearby tampering with the barrier.
As shown in Touhou Bougetsushou, the similarity of the Great Hakurei Barrier to the barrier which surrounds the Lunar Capital means that it is possible to travel between them with a Lunar Veil, or even a specially-constructed rocket, without ever passing through the Outside World. As Yukari's first attempt at invading the Moon predates the barrier's construction, it is possible that Gensokyo's barrier was at least partially based on that of the Lunar Capital.
The broken barrier as seen in Urban Legend in Limbo
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- Perfect Memento in Strict Sense: Monologue
- Strange Creators of Outer World vol. 1: Basic Knowledge of Fantastic Words 2015
- Wild and Horned Hermit - Chapter 25
- Perfect Cherry Blossom— Ending 5 Reimu B. "I don't think even SHE can form such a strong barrier."
- Perfect Cherry Blossom: Prologue
- Strange and Bright Nature Deity: Chapters 23-25
- Curiosities of Lotus Asia: Chapter 11