It wasn’t me! More info, photos and video. It’s amazing it took 50 policemen so long to capture him.
And the 2ch (ni channeru, the world’s largest online community) has gone nuts with artistic renditions:
Naked whitie swims in Japan Palace moat for 1.5 hours
Tokyo Moe 
I live in Tokyo, too…so, of course, I wrote about this story. Here:
http://tokyo5.wordpress.com/2008/10/08/skinny-dipper-in-tokyo/
At the end of that post, I mention our new beetle. As you’re in 中野 (Nakano), have you ever visited the 「カブト虫博物館」 (Beetle Museum) there?
why can’t a flabby bald white man go for a nude swim unmolested? No one would have bothered him in San Francisco
If it were the U.S. White House, and not the Japanese Imperial Palace, within 5 minutes they would have beat senseless a crazed naked foreigner with batons and tasers. If that didn’t work, they would have shot him dead. No?