Equivalent Exchange (等価交換 Tōka Kōkan) is the blanket term for a type of phenomenon featured prominently in the eighth part of the JoJo's Bizarre Adventure series, JoJolion.
Taking on a variety of forms over the course of the part, the concept of equivalent exchange has become a central plot point in the part's overall narrative.
Equivalent exchange is the ability for one thing to be traded for something else of equal value. However, the exact mechanics of this principal's application differ depending on how equivalent exchange is induced. Beyond its various supernatural incarnations, the underlying idea of exchanging one thing for another is a recurring concept present in JoJolion. Notably, the "birth" of Josuke is a result of his two previous identities being permanently lost. This indirectly echoes the sense of responsibility shared by parental figures of the Higashikata family, who on multiple occasions have demonstrated a willingness to sacrifice their own health in order to cure a loved one of the family's unique hereditary illness.
- Main article: Wall Eyes
The area around where the Wall Eyes formed (notably on and around the Higashikata estate) possesses a property that can result in Equivalent Exchange under the right conditions. If two subjects are buried together in close proximity to one another, they will undergo exchange with each other, trading seemingly randomly selected parts for other parts of equal value. A notable example of this type of exchange is demonstrated by Kei Nijimura, who bisects a lemon and a tangerine that had been buried near the Higashikata estate, revealing that corresponding segments of both fruits had been swapped out for one another. So far, this method of exchange has only been demonstrated on organic matter. It is unclear whether or not this type of exchange is possible for things that are inorganic.
As stated by Nijimura, the Higashikata family has been aware of this method of exchange for generations. This knowledge is demonstrated in that through unknown means, this type of exchange can be used to transfer the Rock Disease from one host to another.
Exchange via the Wall Eyes ultimately led to the creation of Josuke Higashikata after his two former identities were buried near the Wall Eyes in the midst of Kira being healed by the New Locacaca he and Josefumi had cultivated. It should be noted that while this type of exchange is seemingly equivalent, the matter which is exchanged does not always directly correspond (the most notable example being the fact that Josuke retains both Josefumi and Kira's pairs of testicles post-exchange).
Daiya Higashikata remarks that she gained her Stand in exchange for her eyesight after falling in a fault that would later become a Wall Eye as a toddler; However, it is not elaborated on in the narrative if these events were genuinely connected or not.
- Main article: Locacaca
The Locacaca 6251 drug developed by members of the T.G. University Hospital staff is able to maximize the healing properties of Locacaca exchange while minimizing the risk of an important sense or organ being sacrificed.
The New Locacaca created by Josefumi Kujo and Yoshikage Kira is able to perform Equivalent Exchange without sacrificing part of the host's body; instead someone in direct contact with them can be given all negative side effects of exchange. This fruit seemingly functions as a mid ground between the two other kinds of exchange.
Upon eating an unripe fruit from their grafted Locacaca branch, the dying Kira's injuries were healed, while parts of Josefumi's body turned to stone, beginning with the areas that had been in contact with Kira upon eating the fruit. However, upon eating the seemingly ripe new Locacaca grown by Jobin Higashikata, Yasuho Hirose experienced a different kind of exchange: upon her arm being regrown Joshu (who had used himself as collateral in the exchange) had his own corresponding arm shrivel up rather than turning to stone.
- ↑ JJL Chapter 17: The Lemon and the Tangerine
- ↑ JJL Chapter 55: Walking Heart, Breaking Heart
- ↑ JJL Chapter 1: Welcome to Morioh
- ↑ JJL Chapter 7: Josuke, Go to the Higashikata Family
- ↑ JJL Chapter 47: Hato Brought Her Boyfriend Home, Part 1
- ↑ JJL Chapter 39: Doobie Wah, Part 1
- ↑ JJL Chapter 92: The Wonder of You, Part 9
- ↑ JJL Chapter 53: Vitamin C and Killer Queen, Part 4
- ↑ JJL Chapter 101: The Wonder of You, Part 18