Four Chinese characters Chong Ning Tong Bao / Chong Ning Tong Bao. 33mm, 12.34 grams. Issued in 1102-1106 AD. Schjoth #621 var.; Hartill 16.402 (for one-sided 5-cash). 

Unique double-sided example. It is probably a privately issued 5-cash coin (private casting of the Chong Ning coins was officially allowed for a short time). The only one known of this type, unlisted in Hartill for a two-sided coin.