These bronze implements are made from an alloy, composed primarily of copper, tin and lead. Shades and gloss vary depending on the ratio between them. Scientific analysis established the average composition for the Kojindani doken : copper is 82%, tin 6.1%, lead 8.6%. The replica implements were newly cast based on this analysis ratio by using a 'stone mold' and a 'sand mold' to re-create the glitter of the Yayoi period.