Important Notes

Exploration Stage: Riverside Abode
From: Detective
Description: Buddy, I found several fubako case on the table. These gilded boxes surely store very important documents, much like an appeal to the Unseen Judges, right? Help me find a relevant scroll.
Completed: Well, well, my intuition did no fail me - there is something in the fubako box decorated with cranes. Firstly, the paper is pink, and secondly, the note is signed by a biwa master. I'm sure this is the missing musician. Here, check it out!