Four Chinese characters Da Ding Tong Bao (the head of "tong" is written as a triangle) / Blank. 25mm, 2.81 grams. Schjöth -; Hartill -; ZhongGuo p.867.
Coins with a "triangle tong" are very rare - unlisted in Hartill, but listed in ZhongGuo catalogue. It might have been some provincial or trial issue.
The Jin Dynasty, also known as the Jurchen Dynasty, was founded by the Wanyan clan of the Tartar Jurchens, the ancestors of the Manchus who established the Qing Dynasty some 500 years later. The Jurcheds carved a large Kingdom out of the Song realm and controlled the northern half of China for over a century, with the southern part controlled by the Song dynasty. The Kingdom came to an end when an allied army of Song and Mongols looted the capital in 1233, and the next year Jin Emperor Aizong committed suicide to avoid being captured. The territory of the Jin was to be divided between the Mongols and the Song.
This coin is unconditionally guaranteed to be authentic