A description of this wonderful music by YouTube user sasayakanaru:
This electronic musical instrument is called “Matryomin“. This was developed by Japanese musician [Masami Takeuchi] ,made by the base of “Theremin” and Russian dall “Matryoshka“.The interval and the volume are controlled by holding up the hand in the antenna in the dall, and changing the distance of the antenna and the hand.
Big hat tip to Billy Sugarfix for sharing this with us on his blog.
Leon Theremin playing his invention the Theremin