kekkai

Kekkai is a Japanese term meaning barrier, boundary, or ward. It can be written with various kanji, most commonly 結界 or 血界, and refers to a protective circle, seal, or territory that delineates or separates spaces, often to keep danger out or to contain other realms.

Etymology and usage: The word combines elements meaning to bind or tie (結) and world or boundary (界). In traditional contexts, kekkai describes protective barriers used in Shinto, Buddhist, and esoteric practices. Talismans, seals, and ritual circles are described as kekkai to ward off spirits, purify spaces, or mark sacred areas. In onmyodo and related traditions, kekkai can denote magical wards that constrain or channel spiritual activity.

In popular culture: The term is widely used in manga, anime, and games to denote magical barriers or zones. A well-known example is Blood Blockade Battlefront (Japanese: 血界戦線, Kekkai Sensen), where a powerful kekkai separates the human world from the Beyond, creating a special district known as Hellsalem’s Lot. In such works, kekkai often function as plot devices that define geography, grant or restrict powers, and shape encounters between characters and supernatural forces.

Other uses: Beyond fiction, kekkai appears in fantasy settings and role-playing games as a mechanic or narrative device representing area-based effects, protective wards, or boundaries around artifacts, locations, or people.

See also: ward, seal, barrier (magic), Shinto purification, onmyodo.