Once a year
There is an "open market" (late October?) for those interested in purchasing a Japanese sword at a building right near the Atago Police Station {across from Japanese Red Cross headquarters}; I don't recall the exact building name [Nihon Token Club Building? Token means "sword & stuff" in Japanese, I'm sure you know what Nihon means... the Japanese word for "Japanese sword" is Nihon-to; or, it may have been Bijutsu Club Building, try that -- Bijutsu means Art -- if Token doesn't ring a bell with the person you ask] but I am fairly certain the policemen and even policewomen nearby know about this place <of course, they may ask you in exchange for your identification card/passport though...>

Mike's