Coin? Charm? Fake? Ancient or modern?
obv: Yumin tongbao 1 Liang "gong" 57mm

I suspect this may be a modern fake (based solely upon some rather more problematic pieces offered by the same dealer). It is, however, a handsome piece. Ding Fubao, in his 1938 edition, identifies this as an ancient fake, illustrating a 67mm example (pictured on p. 220 of Fisher's Ding). But Wybrand Op den Velde remarks:

"the calligraphy is very good and closely follows the official pattern, indicating that it may have been a commemorative or presentation piece. It is certainly never meant for circulation since it is too bulky to have circulated freely or been properly accepted. No contemporary counterfeiter in his right mind would have put that much work or metal into a non-circulating piece." ("Cash Coin Index", Ming Dyn, plate 35)