Answer:
A board zither with 13 silk strings and movable bridges
Step-by-step explanation:
The "Japanese Koto" is a stringed instrument that belongs to the zither family. It was originally played by blind people in Japan. They were the only ones who could professionally play it. The Koto is also said to have been used by the Buddhist monks until it became very popular.
The koto originally consisted of 13 "silk" strings, which were deemed to be expensive yet musical. As of today, most koto instruments are only made of synthetic strings. It has movable bridges which allows it to be tuned. These bridges are called "ji."