Four chines characters Kai Yuan Tong Bao (the jing component of Kai does not touch the hole) / Crescent below the hole. 25.5mm, 3.55 grams. Issued in 621-718 AD. Schjoth #312ff; Hartill 14.1Y.
These are the earliest of the Tang dynasty Kai Yuan issues, as confirmed by the findings of these coins in the tombs dating to the first hundred years of the Tang dynasty. According to legends, the crescent on the reverse of these coins originated when Emperess Wende accidentally stuck a fingernail in a wax model of the Kai Yuan coin presented to her. Out of reversnce, the nail mark on the reverse was not removed but transferred to the copper coins.
The Tang Dynasty, with its capital at Chang'an (present-day Xi'an), the most populous city in the world at the time, is generally regarded as a high point in Chinese civilization - a golden age of cosmopolitan culture. Its territory, acquired through the military campaigns of its early rulers, was greater than that of the Han period, and it rivalled that of the later Yuan Dynasty, Ming Dynasty and Qing Dynasty. In 907 the Tang Dynasty was ended when Zhu Wen, now a military governor, deposed the last emperor of Tang, Emperor Ai of Tang, and took the throne for himself (known posthumously as Emperor Taizu of Later Liang). He established the Later Liang Dynasty, which inaugurated the Five Dynasties and Ten Kingdoms Period. A year later the deposed Emperor Ai was poisoned to death by Zhu Wen. This coin is unconditionally guaranteed to be authentic.