Jin dynasty (1115-1234 AD), Emperor Shi Zong (1161-1190 AD), 'Da Ding Tong Bao', reverse: 'You' above (for the cyclical year characters 'ji you', means 1189 AD). I upload 4 specimens here (i own 6 specimens) and if you can see clearly the upper right one, it's scarce variety with the unusual 'you' character, inside the square of the character, it looks like '/\' compare to other normal variety, and it's larger size too, with different 'Da' and 'Bao' character.