Japanese Coin Shops

So, I am traveling to Japan and I am wondering what coin shops are like in Japan. I have done a little research here and there, but nothing conclusive. I am kind of curious as to whether they have anything comparable to circulated US 90% silver. I’ve seen some sterling 100/1000 yen coins, that and 72% Sen/Yen from just before WWII (those are particularly beautiful)

Basically, I am wondering if anybody may have any experience with coin shops in Japan. I am considering trying to find smaller shops that might trade US silver for Japanese silver. That and just how the shops are or if anybody might have a personal favorite shop in Tokyo or Osaka. Or anywhere else really, I do want to see places other than Tokyo.

Thank you to anybody for the information!