Kekkaishi (結界師?, lit. "Barrier Master") is an ongoing 
supernatural manga series by 
Yellow Tanabe. It is serialized in Japan by 
Shogakukan in the 
manga magazine Shōnen Sunday, and licensed for an English release in North America by 
Viz Media. It was adapted as a fifty-two episode 
anime series by 
Sunrise, which was broadcast between October 2006 and February 2008. The series is about 
Yoshimori Sumimura and 
Tokine Yukimura, heirs to rival families of 
kekkai (barrier magic) users, who must defend their school from the spirits drawn to the sacred land upon which it is built. 
Kekkaishi received the 2007 
Shogakukan Manga Award for 
shōnen manga.
Plot
According to  the legend, five hundred years ago, there was an insignificant lord who  possessed a mysterious power; this power draws 
ayakashi  (supernatural creatures) to him. A demon exterminator, Tokimori Hazama,  was called upon to protect the lord and the castle. The lord's power  stays on the land even when he had died. Thus, Tokimori founded the  Hazama clan, who inherits his techniques, to protect the land for  centuries to come. This land is Karasumori.
In the present day, Yoshimori Sumimura and Tokine Yukimura, heirs of the Hazama clan, are the 
kekkaishi that protect Karasumori. They are ability users (people who can use supernatural powers) who use a technique called 
Kekkai. Kekkai is a form of magical energy barrier which is primarily used to capture and destroy 
ayakashi that are drawn to this 
shinyuuchi  (sacred land). Yoshimori has used an ingenious alternative to plain  barriers by creating boxes of energy which can be used tactically as  weapons or for making airborne stair steps. Any 
ayakashi that stay on the land become stronger. Yoshimori and Tokine are to guard the land from the intrusion of 
ayakashi who intend to power up there.
Yoshimori and Tokine suffered a lot of hardships in their responsibilities to protect Karasumori. The 
ayakashi  they must fight are becoming more and more powerful, but they managed  to protect the land with the help from Yoshimori's older brother,  Masamori Sumimura, and Urakai. Urakai itself is an organization of  ability users that is governed by a council of twelve, consisting of  high level ability users.
Later, it's revealed little by little that the legend is full of lies. The real cause of the 
ayakashi  power up is Chuusinmaru, an illegitimate son of the Hazama clan's  founder, Tokimori Hazama, with the Karasumori clan's heiress who was  named Tsukikage. Tokimori used forbidden arts to grant his son unearthly  power, hoping that his son would grow into a great man who could  conquer the world. However, the plan backfired, as Chuusinmaru was  granted a power to draw people's life force, killing everybody. Tokimori  has no choice but to seal his own son, who has become a too powerful  and dangerous existence, in the Karasumori land, but the seal isn't  perfect, as Chuusinmaru's power still leaks out, powering up 
ayakashi who stay at the land.
Manga
Kekkaishi is written and drawn by 
Yellow Tanabe. It has been serialized in Japan by 
Shogakukan in the 
shōnen (aimed at teenaged boys) 
manga magazine Shōnen Sunday since 2003 issue 47, with publication on-going. Serial chapters have been collected in 32 
tankōbon volumes as of December 2010. The series is licensed in English in North America by 
Viz Media. It is also licensed in France by 
Pika Édition,
[2] in Germany by 
Carlsen Comics,
 in Hong Kong by 
Rightman Publishing Limited,
 in Indonesia by 
Elex Media Komputindo which serializes it in 
Shōnen Star,
 in Italy by 
Planet Manga,
 in Malaysia by 
PCM Comics, in South Korea by 
Bookbox,
 in Spain by 
Editorial Ivrea,
 in Taiwan by 
Tong Li Comics,
 and in Vietnam by 
Kim Dong.
A guidebook to the series called a "teacher's guide" 
(結界師 指南之書) was published as a 
Shōnen Sunday special on 16 December 2006 (
ISBN 4-09-120710-3).
 Anime
Kekkaishi was adapted by 
Sunrise as an 
anime television series directed by 
Kenji Kodama with character designs by Hirotoshi Takaya and music by 
Taku Iwasaki. The opening theme for all episodes is "Sha La La (Ayakashi Night)" 
(Sha la la -アヤカシNIGHT, "Sha La La (Mysterious Night)") by Saeka Uura. There are four different ending themes: "Akai Ito" 
(赤い糸?, "Red Thread") by 
Koshi Inaba (episodes 1–15, 38, 40), "Sekaijū Doko o Sagashite mo" 
(世界中どこを探しても?, "Looking for Another World") by Aiko Kitahara (episodes 16–23, 39, 44), "My Mirai" 
(マイミライ Mai Mirai) "My Future" by Saeka Uura (episodes 24–30, 41), and "Kyūkei Jikan Jūpun" 
(休憩時間10分?, "10 Minute Break")  by Saeka Uura (episodes 31–37, 42–43, 45). The series was broadcast for  52 episodes in Japan between 16 October 2006 and 12 February 2008 on 
Nippon Television, 
Yomiuri TV, and 
Nippon Television Network System, in the "golden" timeslot of 7 p.m. Monday.
The anime has been licensed in North America by 
Viz Media.
 which began broadcasting episodes online through 
Hulu.com in January 2010.
 The series premiered on TV on May 29, 2010 on 
Adult Swim.
 It has also been broadcast in Taiwan on 
TTV and 
Videoland Television Network, in Malaysia on 
8TV (Cantonese dubbing with Malay subtitles) and 
NTV7 (Malay dubbing), in Hong Kong on 
Cable TV, in the Philippines on 
Hero and 
GMA-7, and in Indonesia on 
antv.