what is a domain expansion

Domain Expansion is a technique used in the Jujutsu Kaisen anime and manga series. It is the most advanced technique in Jujutsu Sorcery, which allows the user to manifest a barrier within their innate domain and trap their opponent inside it. The technique involves expanding ones innate domain with cursed energy while using a barrier to create a separate space and imbuing every inch of that space with the users technique. The resulting domain can take many forms, such as a peaceful beach or a scorching sea of magma and raging volcanoes. Domain Expansion is considered the most difficult and supreme ability that can be obtained. Only a few Jujutsu Sorcerers can activate their Domain Expansion, and it is incredibly rare and costly to use. The strength of a sorcerers Domain Expansion is an indicator of their power level.