5 Yuan piedfort, 1992 Inventions and Discoveries - 1 st edition, 5 Yuan piedfort issues complete, 5 pieces, all NGC certified PF 68 ULTRA CAMEO, 1) bronze Age Metal Working KM-P25, 2) Ancient Compass KM-P22, 3) Shipbuilding KM-P21, 4) butterfly Kites KM-P24, 5) First seismograph KM-P23, including Co As for each coin, a wonderful historical reappraisal of China cultural heritage, PF 68 ULTRA CAMEO.