Bronze pattern for iron coins. Jin Dynasty (1115-1234 AD), Emperor Shizong (1178-1189AD), 'Da Ding Tong Bao'. 2.8g, Bronze, 23.69mm. This is the iron mould bronze pattern (in Chinese: Tie(3) Fan(4) Tong(2)), the bronze trial cast model for coin inspection purpose to ensure the quality before cast iron coins officially. Good very fine and rare.