China
People's Republic Inventions & Discovery Proof 100 Yuan 1993 PR69 Ultra Cameo NGC, Series II, Yin & Yang, KM508, Fr-75, Cheng page 136, number 2. Superb cameo appearance, with a bold strike and no noticeable flaws. Much rarer than its listed mintage of 888 pieces suggests.
Estimate: 10000-15000 USD