Okinawa Sanshin String Instrument with Soft Case, Backpack Type

This item has been used.
I studied for about a year, but had to quit due to hearing loss, which made it impossible to learn by listening.
There are sheet music attached to the top of the case. I would appreciate it if you could take the sheet music as well.
My teacher, who taught me, said it was a very good item and I purchased it for 55,000 yen.
The color of the body is not black, giving it a soft feel.
I don't know the material, so I would appreciate it if you could get a sense of it from the photos.
It has a rough texture, possibly snake skin.

Please understand that this is a long-term home storage item and has been inspected by an amateur before purchasing.

I will wrap it in plastic wrap, then bubble wrap, and then double-layer it in a large plastic bag for shipping.
It will be delivered via Yu-Yu Mercari便 or Raku-Raku Mercari便.

Thank you for looking 