The Hierophant Arcana
In order for the player to unlock the Hierophant Arcana he'll need max Charm and also it'll have to be later than April 25th ingame. The two ingame characters associated with the Hierophant Social Link are Bunkichi and his wife Mitsuko who own the Bookworm store at Iwatodai Station (in the picture below).
The first time that you visit the old couple they'll talk to you about a Persimmon Tree that is located at Gekkoukan High. To befriend them you'll want to bring them a leaf from this Persimmon Tree (which you can inspect/pick the leaf up once you've spoken to these two). Doing so will begin the Hierophant Social Link.
If you want directions on how to find the tree check below!
After hearing about this head to the tree which is located through the double set of doors on the first floor of the school. If you're having trouble finding it, when you enter the school from the front entrance it'll be off to the right. Follow the hallways until you find a long set of doors; the doors will lead to a courtyard like area that has the Persimmon Tree just off the path.
Inspect it for the leaf that you'll need to bring back to the old couple. If you are still having trouble finding it; A picture of the Persimmon Tree can be found below.
Bunkichi and his wife Mitsuko's relationship involves quite a bit of drama about this tree and their son who the tree was planted in remembrance of. Another unique thing about this Social Link is Bunkichi always gives you an item when you come to visit. You should accept the items from him each time, declining them will just upset him.
While raising a Social Link you'll be given story cutscenes where you'll have to answer questions. The answers to each of these questions is different depending on the person and the situation. What you usually need to try and do is pick an answer that reflects their personality. Here's a cheat sheet for each Social Link rank of the Hierophant Arcana and what to say.
Rank 1: Automatically earned
Rank 2: (Tell him) - Thanks - Anything - Anything - Anything
Rank 3: Looking for something? - I'll help you look - Anything - Anything - Anything
Rank 4: Anything - Anything - Now you have me worried
Rank 5: I'll root out the truth - Anything
Rank 6: Please stop quarreling - Anything
Rank 7: Ask why Mitsuko is crying - That's great - Anything
Rank 8: Anything - Anything - Anything
Rank 9: Anything - Anything
Rank 10: Automatically earned
When you complete this Social Link you'll be able to fuse the Persona Kohryu through Cross Fusion by combining Byakko, Suzaku, Seiryuu, Genbu.