The Jujutsu Kaisen ranking system is used to assign grades to sorcerers, differentiating them based depending on strength, intellect, and battle ability. This system was created by jujutsu sorcerers to evaluate both themselves and the curses they hunt, and the technical system includes seven different grades a sorcerer can achieve, starting with Grade 4 and ending with Grade 1. While there is a special grade rank reserved for those with immeasurable cursed energy and heightened destructive potential, this rank is exclusive to jujutsu anomalies like Yuta Okkotsu, Suguru Geto, and Satoru Gojo.
Source：https://www.cbr.com/who-is-jujutsu-kaisens-strongest-grade-1-sorcerer/
