Four Chinese characters Zhi Zheng Tong Bao / Phgas Pa word shi ("10" for “10 cash”) below. 45mm, 22.1 grams. Issued 1350-1368. Hartill 19.115.

Huge coin of the last Yuan dynasty Emperor. It it fairly high grade ("80", equivalent to about EF), but is covered in original very thick green patina. The characters are complete and the coin is problem-free. 

Emperor Toghon Temür (r. 1333–1368), also known by his temple name Emperor Shun of Yuan, was the last ruler of the Mongol-led Yuan dynasty in China. Ascending the throne as a teenager, he spent much of his reign under the influence of powerful ministers and court factions, while the dynasty weakened due to corruption, factional strife, economic distress, natural disasters, and widespread rebellion. His rule saw the rapid decline of Yuan authority, culminating in the rise of the Red Turban movement and the advance of Zhu Yuanzhang, founder of the Ming dynasty. In 1368, Toghon Temür fled the Yuan capital of Dadu (Beijing) to Mongolia, where he continued to rule the Northern Yuan until his death, marking the end of Yuan rule in China proper but not the extinction of Mongol imperial authority.