Four chinese characters - Kai Da Tong Bao / Chinese character Si (="4") above the hole. 23mm, 3.2 grams. Schjöth #-; Hartill #15.143."Da" on obverse is a clear error for "yuan". "4" on reverse is probably either a date or a control mark of some sorts.Chu was a kingdom in southern China during the Five Dynasties and Ten Kingdoms Period (907-960). It existed from 907 to 951. Ma Yin was named regional governor by the Tang court in 896 after fighting against a rebel named Yang Xingmi. He declared himself as the Prince of Chu with the fall of the Tang Dynasty in 907. Mas position as Prince of Chu was confirmed by the Later Tang Dynasty in the north in 927 and was given the posthumous title of Chu Wumuwang. After Ma Yin died the leadership was subject to struggle and conflict which resulted in the fall of the kingdom. The Southern Tang, fresh from its conquest of the Min Kingdom, took advantage and conquered the kingdom in 951. The ruling family was removed to the Southern Tang capital of Nanjing and the kingdom was absorbed into the Southern Tang.This coin is unconditionally guaranteed to be authentic.