Recently I heard that since 2008 the Japanese Mint is issuing a series of commemorative coins (1000 yen in silver and coloured on one side; and bimetallic 500 yen) depicting each of the 47 prefectures of Japan (similar to the 50 States Quarter Series in the U.S.). The series will be completed in 2016. As far as I know, the silver Hokkaido and Kyoto coins have already been issued and, as for the 500 yen coins, Hokkaido, Kyoto and Shimane.
I'm desperate to receive my first coins (thanks to eBay).
Also, does anybody know where I can buy a decent sized wall map of Japan with the 47 prefectures depicted in different colours for clarity's sake? I recently bought one from amazon.co.jp but I'd like to get some other with stronger colours and a bit bigger.