What does 領域展開 Ryouiki Tenkai mean?

Ryouiki tenkai is Domain Expansion, a technique of the sorcerers in Jujutsu Kaisen. The English name is close to literal; what it loses is that both Japanese words are ordinary dictionary vocabulary, and that tenkai is less about getting bigger than about unfolding.

The kanji, taken apart

領域 (ryōiki) joins 領 (ryō), which KANJIDIC glosses as jurisdiction, dominion or territory, with 域 (iki), range, region or limits. 展開 (tenkai) joins 展 (ten), unfold or expand, with 開 (kai), open or unseal. All four are standard school characters, and all four are read here with their ordinary Sino-Japanese readings.

The two words in ordinary Japanese

Daijisen defines 領域 as the range that a force, action or rule reaches, or that a person or thing is involved with, with examples like the human unconscious and the field of theoretical physics. It is also the international-law term for the area under a state's sovereignty (land, sea and air), and a computing word for a storage area.

Daijisen lists spreading something out widely; unrolling something such as a great debate or a performance; moving to a next stage, as when a stalled negotiation moves on or a case develops in an unexpected direction; and spreading out something that was massed together. The Nihon Kokugo Daijiten, on the same page, makes the military sense explicit: a massed unit of troops opening into extended order, citing an 1881 military glossary. It also has two mathematical senses: multiplying out an algebraic product, and unfolding a polyhedron flat onto a plane. JMdict includes (plot) twist among its glosses, alongside deployment.

The compound 領域展開 itself has no entry in Kotobank's dictionaries or in JMdict, both checked on October 7, 2026; it is Jujutsu Kaisen vocabulary.

What it means in Jujutsu Kaisen

In a January 2021 Crunchyroll interview, read through the Internet Archive, director Sunghoo Park describes the work of depicting and constructing each character's domain expansion. In a February 2021 Anime News Network interview, Park named the Domain Expansion scenes as especially difficult to create: the manga is black and white and static, so the team had to decide how to build a three-dimensional space and what color it would be, in discussion with the author Gege Akutami and the publisher Shueisha.

Each domain has its own name. Satoru Gojo's is 無量空処, which Crunchyroll's English text of the Park interview gives as Infinite Void. An April 2020 Real Sound article on the manga describes it as forcing an infinite number of operations onto the act of living, perception and communication included, so that, given all the information at once, the target cannot act of their own will at all. Both halves of the name are dictionary words: Daijisen defines 無量 as immeasurably many, and the Nihon Kokugo Daijiten gives 空処 as another name for 空無辺処, a Buddhist term for the first of the four heavens of the formless realm, the sphere of boundless space. No source checked says which of these the author had in mind.

Expansion or unfolding

Domain Expansion is a fair translation, and in one sense an exact one: English also says expand for multiplying out an algebraic expression. But the first meaning of 展開 is spreading out or opening up, and its geometry sense is the flat net of a folded solid. Domain deployment would catch the military sense; domain unfolding would catch the geometric one.

One reading of the remaining difference is register. The dictionary senses of both Japanese words run through law, computing, mathematics and military drill, so ryōiki tenkai can read as procedure: territory, deployed. English expansion, as in expansion pack or expansion slot, pulls the name toward growth and upgrades.