The Ku-chin - the oldest Chinese stringed instrument is common in all Eastern and South-Eastern Asiatic countries. It has got different variants!
Thus the instrument shown above may also be a Korean Kajagum! Or a 16-string Hsiao-se.
Whatsoever - all the dimensions of the instrument are symbolic: the length of three feet, six inches and six lines results in the 365 (366) days of the year. The width of six inches stands for the north, the south, the east, the west, zenith and nadir. The bottom is flat like the earth, while the soundboard is convex like the sky.