my friend found a bunch of coins in this set of all the various emperors in a market in china town in singapore. numista gives them all ~60 for rarity but im not sure what that is based on and they have no other info. i am wondering when these coins were made (assuming the dates on them are just the reigns on the emperors, not their creation date), if they could be fake, how much theyre worth, etc. i am specifically interested in this coin and the one of hong taiji, but any info is welcome. thanks!