The koto is a plucked, 13-stringed wooden instrument with moveable bridges allowing for variable tuning (guitar players are drooling right about now). It sounds so distinctively Japanese that it's their national instrument. It's rarely found in Western music, although both John Coltrane and McCoy Tyner incorporated its 5-note scale in some of their music, and David Bowie and Brian Jones (of The Rolling Stones) managed to work it into one song apiece over a long stretch of releases.
Visual kei band Kagrra, (apparently one of my favorites here, 'cuz I've posted their songs previously here and here) moved heavily into the koto-based sound that gave them their distinctive Japanese flavor. (Well, all the kimonos and yukata they wore helped stress their Japanese-ness, too, I think.) Shin, one of their 3 guitarists, took up the ancient instrument and really began using it much more in 2005, with the release of San, and later. See how his guitar is still hanging around his neck as he plucks the koto in my photo. Can we say musical multitasking?