https://blog.faceutil.com/2017/03/26/%ec%8a%a4%ec%b9%b4%ec%9d%b4%eb%a6%bc-ancient-blades-weapons-%eb%8b%a8%ea%b6%81%ec%9d%84-%ec%82%ac%ec%9a%a9%ed%95%b4%eb%b3%b4%ec%9e%90-%ec%82%ac%ec%8a%b4-%e3%83%b1/