As we all know, the fineness and complexity of the frontal portraits are able to prevent counterfeit banknotes to the utmost extent. The size of the coin itself is small, and the difficulty of drawing a frontal portrait on the metal surface will multiply, and the difficulty of recognition will increase accordingly.

Even if the technique of drawing a frontal portrait of a coin can be achieved, the cost is greatly increased. In addition, as the coin is circulated, the details of many frontal portraits are quickly worn out, and the use rate of the manufactured goods at a large cost is greatly reduced.