koto vs qing

koto

noun
  • A Japanese stringed instrument having numerous strings, usually seven or thirteen, that are stretched over a convex wooden sounding board and are plucked with three plectra, worn on the thumb, index finger, and middle finger of one hand. 

qing

noun
  • A sounding stone, a Chinese musical instrument. 

How often have the words koto and qing occurred in a corpus of books? (source: Google Ngram Viewer )