This saddle-shaped ground stone knife was made by grinding metal and stone; the back of the knife is concave, while the edges of the back stand out to form a horn shape that also resembles a saddle. The bottom of the blade is further ground and processed to create a side chopper with a hole in the middle. Such stone knifes were usually tied to a rope and hung on the wrist, so that the user could use it to collect rice. Based on the shape of the object, it is assumed that it originated from late Beinan culture in Eastern Taiwan during the Neolithic Age (circa 3,500~2,300 years ago).