thank you for the comment.
i regularly check the list of all geocoins at the link provide above and i am 99.99% sure i have not seen this geocoin in the list before. i also cannot find any 'Japan Spring Geocoin' when searching at gc.com site. plus i checked the geocoinstore.com coin museum and i did not find the coin either. it all leads me to think you are problaby wrong. as far as i know japan geocoin issued in 2008 was 'japan summer geocoin', not 'japan spring geocoin'.
well, i hope soon an information about it will pop up somwhere.