I got to visit the shops when on vacation, just jaw-dropping. We had the Tokyo Underground book with us and saw the guy with the glasses in the book working that day. Showed him his photo and he was really happy about it.
but you gotta admit, the shop was a pain to track down. all i saw were rubber knockers on sale in buckets right off the train station
the 7 story mandarake store, with mandarake on the side of the building, was tough to track down? I didn't have a map, but we found it a-ok. A friend told us which direction to head when we got off the train, wasn't too bad in my opinion. That store is incredible, somewhat expensive but given what you can pick up there... jyarinco on the other hand...that was the only one i had trouble finding