http://cnews.canoe.ca/CNEWS/WeirdNews/2007/10/20/4591795-ap.html Im surprised that he would receive it after so many years.
The answer: "It said the card had initially failed to reach Nagano's address in Nagasaki, and was instead collected there by an American soldier during the U.S. occupation after Japan's 1945 defeat." Happily Shizuo Nagano received the card before s/he die. Better late than never.