Warning! Spoilers ahead for Jujutsu Kaisen chapter 171!
Before now, Jujutsu Kaisen had ostensibly revealed everything fans needed to know about the supreme jujutsu technique Domain Expansion. But mangaka Gege Akutami just introduced an innovative way to give his domains another twist - by making a vulnerability a massive strength during the Culling death battle games.
In chapter 171, Megumi Fushiguro uses his current (and ridiculous) Culling opponent's knowledge of Domain Expansions against him to once again leverage these advanced barriers innovatively. Severely weakened from his previous battles, Megumi temporarily flees from the receipt-wielding Reggie Star to summon his Chimera Shadow Garden inside a nearby gymnasium. But as Reggie realizes, the fact that Megumi converted the gym into the required barrier for his domain means that the actual barrier is now incomplete. This, in turn, nullified the true power of Megumi's domain - which is to ensure that every attack makes with his target - causing this garden of shadows to compensate by extending and amplifying Megumi's Ten Shadows technique instead. Reggie's understanding of how domains function, therefore, ended up working against him because Reggie's initial strategy was based on the fact that he wouldn't be able to dodge Megumi's attacks, catching the villain off guard when he did. Unfortunately, Reggie comes to this realization sooner rather than later.
This aforementioned phenomenon is actually an extension of an earlier moment that transpired during the Shibuya arc. The main functionality of Domain Expansions ensures that the wielder's attacks will never miss their target. But, in Shibuya, the curses Jogo and Hanami were able to create a domain that took this power to the next level by making it so their attacks would automatically kill their opponent. But instead of leveraging that increased power for their attacks, they used that additional capability to empower another ability in their domain that is otherwise impossible: Channeling Gojo's power to neutralize the Limited Curse technique. Unlike Megumi's current "trick" this only throws Reggie Star off briefly and he reassesses his strategy to turn it against his opponent. Of course, Megumi being who he is flips Reggie's new tactic against him in a matter of moments.
This is just the latest example of Jujutsu Kaisen updating its most ubiquitous technique in the same manner as other successful shonen series. Shonen are notorious for introducing already complex battle systems to readers before complicating them further down the line. Long before now, Megumi once again changed everyone's basic understandings of Domain Expansions. In chapter 109, Megumi's utilization of Chimera Shadow Garden against his opponent's stronger domain introduced another reason why a sorcerer would attempt this. Before now, jujutsu s would only do this to try and conquer their opponent's domain with their own. But in that particular case, Megumi summoned his advanced barrier to poke a hole in his enemy's much stronger domain to escape (which is nearly impossible).
Megumi's current battle against Reggie Star along with the two cursed spirit's confrontation during Shibuya prove that wielders can shift certain capabilities of their Domain Expansions to empower other areas of their barrier. Jogo and Hanami took a power that exceeded the normal functionality within their domain and diverted that excess energy for another unprecedented use. Megumi basically achieved a similar outcome but through opposite means by intentionally weakening a certain aspect of his domain to empower another. How Jujutsu Kaisen will continue to transform readers' understanding of Domain Expansions is anybody's guess, but it's sure to be as captivating as the last.
