Responses

MC was writing a complaint letter to the guards (or whomever in the prison) about Jingi being abusive and also mentioned Heonjae. MC had to put their inmate numbers in the letter and he mixed up the last two numbers of Heonjae’s but knew Jingi’s. Heonjae saw this and his feelings got hurt that Jingi didn’t remember his. Within the prison, not knowing the number is like not knowing his name. (95% sure off the top of my head on this, it was a few chapters back)
Can someone explain why the inmate number matters? I want to avoid re-reading if at all possible…