Need Help With This Chinese Coin (Id: 12th Century Chinese Multi-Cash Emperor Huizong)

First off, your pic is upside-down.



There, that's better.

I assume it's quite large? It looks like a multiple-cash from the reign of the Song Dynasty emperor Huizong, during his Chong Ning era (AD 1102-1106). Hiuzong was an incompetent emperor who eventually lost his empire to Jurchen invaders, but he was a talented calligrapher, and is said to have designed the "slender gold" script used on these large fancy coins himself.

Examples on the zeno.ru database can be seen here: https://www.zeno.ru/showgallery.php?cat=8560

Despite being so old, they aren't all that rare or expensive, compared to European mediaeval coins from the same time period. I think I paid just $20 or so a few years ago for the example in my collection. So not worthless, but not super-valuable either.

So, is it genuine? That's a less easy question to answer. Fakes of these coins do exist, because Chinese people do find the unusual calligraphy to be beautiful, and the fake patina you find on these fake coins can range from laughably silly to convincing to completely absent. The patina on your coin looks very convincing to me, so I'm inclined to assume it to be genuine.