This is an oto-o (sound string) for Nagauta shamisen. I use this for Tsugaru-jamisen and Jiuta-shamisen. Since it has the same width as the thread path of the koma (bridge), the strings are aligned straight, resulting in a clear and crisp sound. I was taught this by my Tsugaru-jamisen teacher. Made of pure silk with gold thread woven in. It looks very cool. - Color: Navy blue - Material: Pure silk - Purpose: Oto-o (sound string) - Features: Decorated with gold thread Thank you for looking.