The Yuan Shih-kai dollar or ”Fatman” dollar is one of most common Chinese silver dollars. They are also among the most commonly counterfeited Chinese coins, with counterfeit examples common for all four dates and several other major varieties. The Yuan Shih-kai silver dollar was first introduced in 1914. It has a silver purity of 0.8900 and weighs 26.40 grams. The coins are nicknamed ”Fatman” dollars which leads one to believe it is due to the stature of the leader but Yuan was merely a stout man. The literal Chinese translation is ”big head,” which is a more accurate description.

1. Basic checks

First I usually check the weight (26.4 g) and diameter (37 mm) so that they match very accurately. After that I check possible special features of the coin and Fat Man Dollar does has some special features.

2. Ping test

I’m using a mobile app called Bullion Test and the Pocket Pinger, which makes it easier to hold the coin in place and create a vibrating sound.

The picture above shows four coins of mine. Can you tell which one or more are fakes?

Here you can see the test results, weight and resonance. To confirm my own tests, this time I also tested all these coins with XRF and those results are the column Ag-content (%).

Weight (g)        Resonance (hz)                        Ag-content (%)

27.50                6739                                            0

26.08                3919                                            97.8

26.73                3983                                            97.2

26.65                4005                                            97.2

As you can see the first coin weighs a bit too much and the resonance is much more compared to the other three coins. The XRF-test confirms that the Ag-content of the first coin is 0, alloy being copper, zink and nickel.

To be able to draw reliable conclusions from the resonance frequency results, you need to know the correct resonant frequency of the corresponding real coin, or at least a coin with similar characteristics.

The image below roughly shows the resonant frequency of silver coins in relation to the diameter of the coin based on my tests.