Commonly known as a "fatman dollar". Many varieties exist. There are 2 types of them: 50 CENTS (1/2 YUAN) 30 mm diameter, 0.306 troy ounces silver 1 DOLLAR (1 YUAN) 37 mm diameter, 0.755 troy ounces silver These are hugely counterfeited. At 1st glance, yours looks real.
Actually there are 4 types. of which only the Yuan circulated. The 50 cent version and the 10 cent (2.7g .700 silver) and 20 cent (5.4g .700 silver) versions you forgot about, were all minted as specimens only. Age is not an indicia of genuineness as there were plenty of contemporary counterfeits, and many of the "souvenir" versions had been produced in the 50+ year span preceding yours being placed in that chest.
that is year 3 - so 1914 test with a magnet is a good first test - if magnetic then fake - if not need further testing but I am not an expert on those so somebody else would need to help you if it is non-magnetic
Actually the very first step is to read the legend above Yuan Shih Kai's head. If you don't read Chinese, just count the characters. On a coin dated Year 3 (1914) the count must be six, and for Year 8 (1919 it needs to be 7. The next steps would be diameter - 32mm - which is correct on most counterfeits; and weight - 26.4g - which is frequently off, usually to the low side. Any coin passing those tests must have its edge examined. Genuine coins may be reeded, plain, have circles all the way around, or have Ts all the way around, alternating orientation. Most fakes are reeded, so that test usually gives inconclusive results. Finally, an experienced collector, either by an in-hand examination, or by reviewing high definition, life-size or larger photographs, will consider certain design details, especially including the shoulder boards and the reverse foliage, and the calligraphy or style of the characters. Personally, I would never confirm genuineness solely from photographs, no matter how large or how good the definition.
Are you kidding? Japanese coins are seen by at least as many numismatists as those from England, France, South Africa, Australia, and other major countries of the world; and more than those who have seen coins from Senegal, Nepal, Paraguay, and other smaller countries - not to mention the 128-million residents of Japan and it's hundreds of thousands of annual visitors. It's also somewhat curious that you choose a thread about a Chinese coin to make that comment in.
No you missed his joke. He was poking fun at a typo. I've ssen a lot of coins from Japan, but I haven't seen any coins from Iapan.