Hi yalehockeymom,
I saw your geocoin when I was there (in Kobe) back in February and I wrote down the tracking code. I am pretty sure that your coin is still there and do not be afraid about the long time the cache and your coin were not found. There not (yet) so many cachers in Japan and it can take a long time until the next one is going all the way up to the cache.
Best regards and greetings from Germany
Enrico