7a. A VERY RARE large 'Xian Feng Tong Bao' (咸豐通寶) 1 cash coin, cast by the Qing Dynasty Board of Works (BoW - 工部) Mint in Beijing during the reign of Emperor Xianfeng, who ruled over China, from 1851 to 1861 AD. What makes this particular coin very rare, is its unusually large size, which is larger than the smaller 10 cash coins cast in the latter part of his reign. The larger sized cash coins indicate it was cast very early in the reign of Xianfeng. 27mm in size; 6 grams in weight.