The Bowed Psaltery consists of a scale of individual strings each tuned to a specific pitch and arranged to be played upon one at a time by a bow. Each individual string is a musical instrument in its self called a Monochord. Monochords are the earliest stringed instruments with all other stringed instruments progressing from that first development. Many different Monochords were developed by many cultures through out history. One of these, the Vietnamese Dan Bau, sometimes described as a prehistoric Theremim, is quite amazing for the variety of harmonic effects it can produce. Pham Duc Thanh is the consummate master of the Dan Bau and on his YouTube channel you can hear him play more traditionally, however for a fun first experience of the instrument I have chosen here his version of "GHOST RIDERS IN THE SKY".....https://youtu.be/pqb-tI2ydjY The Dan Bau is often played as a part of Vietnamese Water Puppet Shows. Be sure be see one of those videos.