Hi chinese item,
I think this coin is genuine!

I have also one dollar Yuan Shih Kai 1921 with "T" letter on obverse and on the reverse is very strong shade below the chinese word "Yuan". Take a look on my picture. I also have 10 cents Yuan Shih Kai with similar share on reverse. I noticed that you asked this question on many coin forums, like
www.cointalk.com or some others. About this huge round and straight lines, I am not sure, but you can try contact with "expat" who is moderator on Russian coin forum:
www.zeno.ru"expat" is an expert from Beijing. He saw a lot of coins and he can help you if you will post your coin over there. But coin must be on white background, also show them edge of your coin. To register over there you will have to contact with "charm" (his name is Vladimir), his is a Russian guy and his owner and administator of the forum. Just send him email on
charm@postman.ru and he will ask you to give yourself some nick name, after you will give him nickname, he will send you temporary password to login zeno.ru . Post later image of your coin there and "expat", "Chinasmith" and "Vincent" will help you for sure. If you are Chinese or can understand chinese you can contact also with other coin collectors from China at
www.coinsky.com. Good luck my friend. Ohh, send greetings those guys from zeno.ru from me. I miss this forum very much
