Social Links are a gameplay feature in every Persona game that enables you to unlock Arcana and Ultimate Personas. In some cases, a Social Link may be locked behind another Social Link. One example of this is Persona 3 Reload's Justice Social Link, Chihiro Fushimi. However, you'll need to speak with Chihiro after class on several occasions before you can formally unlock the Justice Social Link. You'll want to be careful what you say, as choosing a "wrong" answer will delay you from getting Justice (Social Link) Rank 1 in Persona 3 Reload.