These semilunar stone knives discovered at the archaeological site in Songguk-ri in Chochon-myeon, Buyeo, Chungcheongnam-do represent agricultural development in Korea during the Bronze Age. The tools acquired their name due to their shape, although this varies according to when and where they were made. One of the two relics has the form of a short boat, whereas the other is triangular, and is known to have been more effective in reaping crops. Farming tools such as these are known to have been invented after the spread of rice cultivation across the south of the Korean Peninsula.