“Mirrors,” the southern enchanted wall of Otosan Uchi.
Komachi's Travel Guide
The southern wall of Otosan Uchi is an enigma. An Isawa named Naigama conceived and executed the enchantments upon it, along with his pupils, who represented the best shugenja in the Empire. All of them were consumed in the process, swallowed up by the walls they helped create. No one could be certain that the wall was protected at all until the second wave of the Battle of Four Winds, when the attacking oni were mysteriously destroyed by an army of elemental dopplegangers and the wall itself.
After the Battle of four Winds, the Asahina requested the right to study the wall using their tsangusuri techniques. Hantei II and his council found this a novel approach, and approved the request; the Asahina became the official guardians and researchers of the Southern Wall. Within weeks, they created and installed thirteen talismans, fashioned in the shape of mirrors made from their relative components (wood, fire, earth, water, and metal). The mirrors were designed to observe the spirits of the wall, and eventually to make contact with them. Alternately, the Asahina could use the mirrors to watch the spiritual patterns of the wall, looking for evidence of the oni or other corruption.