This coin has been identified to a reasonable certainty, to be a Yuán-Fēng Tōng-Bǎo. The coin is of a cash type, estimated to be 1 cash value. Coins of this type were a "universal currency", issued from 1078-1085 CE. During the 2nd era of Emperor Zhenzong (1082-1135CE). Who was the ruler of the Northern Song Dynasty, from 1048-1085 CE.
The coin is appears to be possibly made of "white bronze", a bronze alloy containing zinc. With an estimated width of 24mm (0.945 in) and weight of 3.25g.Its rim is a conventional type, being relatively wide and raised. The central hole is a common type, with a square hole. The hole's rim is relatively thin, done to make way for the coin's Hanzi characters.
Historically this coin type was known to be produced in an impressive 19 mints, located in 11 providences. The list of providences included Ezhou, Jianzhou, Huizhou, Shizhou, Wanzhou, Hubei, Muzhou, Shuzhou, Hengzhou, Chizhou, and Raozhou. Including the military garrisons of the Tongyuan and Nanping Army.
Observe
The coin's characters are read clockwise, in Running Script. They read 元 (Yuan), 豐 (Feng), 通 (Tong), 寶 (Bao). It should be noted the Running Script is a semi-cursive form of Hanzi. It originated from the calligraphy of imperial court scribes, during the the Han Dynasty (202 BCE-220CE).
Reverse
In regards to the reverse, this example is blank. Although reverse details were some what uncommon, until later dynasties. Coinage of the Southern Song (1127-1179) feature small reverse details, such as a "Star and Moon" charm. Other examples include a single Hanzi character, such as 元 (Yuan), 三 (San), and 六 (Liu). These character representing the "first", "third", "sixth" year of rule, respectively.
Size Comparison
Additional Notes
The uses of multiple mints was historical common in cash coin production. Creating a large degree of variation, until the machine struck coins of the late-Qing Dynasty (1636-1912 CE).
Historically cash coins were at times made of alternative metals, other than bronze. The common alternatives being brass, copper, and iron.
After the introduction of Kāi-Yuán Tōng-Bǎo coins, in 621 CE. The value of cash coin became based their inscription, rather than their composition.
Bronze ceased being the standard for cash coins in 1505. Cheaper brass coins became the new standard. Coins produced during the late Qing Dynasty contained higher levels of lead and tin, giving them a yellowish tin