From Wikipedia: The Song dynasty (/sʊŋ/) was an imperial dynasty of China that ruled from 960 to 1279. The dynasty was founded by Emperor Taizu of Song, who usurped the throne of the Later Zhou dynasty and went on to conquer the rest of the Ten Kingdoms, ending the Five Dynasties and Ten Kingdoms period. The Song often came into conflict with the contemporaneous Liao, Western Xia and Jin dynasties in northern China. After retreating to southern China following attacks by the Jin dynasty, the Song was eventually conquered by the Mongol-led Yuan dynasty.

The Northern Song dynasty of China was a very prolific coin producing period. For coins which are over a thousand years old, they are relatively cheap and easy to come by (though beware of counterfeits).

Like most Chinese “Cash” coins, it is round, with a large square hole in the center. Cash coins were cast from molten bronze in “trees”. Luke Roberts has some good pictures on his Coin Treet page.

After casting, the coins were separated and placed on a square rod, and then the outsides filed to give a smooth edge, this is why they have a square hole in the centre. The obverse of most “Cash” coins contains four symbols. These are often read top, bottom, right left. In this case, the symbols are: Xuan 宣, He 和, Tong 通, Bao 寶. Xuanhe was the sixth era of the Huizong dynasty, 1119-1125. There are several different translations for “Tong Bao” but it is common to most Chinese coins and basically means “coin”. Song dynasty coins often came in “pairs” where coins of the same style appear with different scripts. This coin has characters in “Seal script”. There are also coins with “Clerkly” script and “orthodox” script. In some cases the scripts look similar, but in other cases, they can look very different. Here is a coin with the same characters in “Clerkly” script:

Here is the reverse of the first coin:

The reverse of many coins contains two characters indicating the mint. In some cases, such as this one, the reverse is blank.

Norman F. Gorny has produced an excellent book, “Northern Song Dynasty Cash Variety Guide”, which is available from Norman’s website.

The majority of Chinse cash coins are 1 cash coin. This particular piece is a 2 cash coin, which is not denoted by anything on the coin, but rather by the size, which is slightly larger. Here it is next to a 1 cash coin from the same era: