I had been in Japan until 2007 (now in California) and did some brevets in Tokyo area. Hope I can help you.

There's no centralized route database in Audax Japan, but it has links to regional brevet organizers.
Most of them lists route sheets & maps.Here's a list of links to regional organizers.
  http://audax-japan.com/Link.html

For Osaka area, check out Audax Kinki. I found 2012 routes at http://audax-kinki.com/2012/2012brm.htm
At the bottom of this page, there are links to the routes for the past years.

For Tokyo area, there are lots of regional organizers (more than one per prefecture).
* Audax Kanagawa (Kanagawa Pref) http://www.aj-kanagawa.org/
    2012 routes: http://www.aj-kanagawa.org/2012-brm
    (Click the links at the very bottom)

* Velo Club Randonneurs Aoba (Kanagawa pref) http://www.vcr-aoba.org/
    2012 routes: http://www.vcr-aoba.org/2012

* Audax Chiba (Chiba Pref) http://ajchiba.web.fc2.com/
    2012 routes: http://ajchiba.web.fc2.com/topmenu/brm2012.html

* Audax Nishi-Tokyo (West Tokyo area)  http://www.ajnishitokyo.org/

* Audax Shizuoka (Shizuoka pref) http://sites.google.com/site/audaxjapanshizuoka/

* Audax Saitama (Saitama Pref)  http://audax-saitama.org/
    2012 Routes: http://brm.audax-saitama.org/
    (There's a link for the past years on the bottom)

* Audax Utsunomiya (Tochigi Prefecture) http://www.geocities.co.jp/ajubrm/
    The top page has links to 2012 routes

* Audax Gunma (Gunma Pref) http://www.aj-gunma.org/
    2012 routes: http://www.aj-gunma.org/p/brm_28.html

BTW, they have a convention in naming routes, something like BRM + Month + Date + Location(or nickname) + Distance (in km).
For example,  BRM421富士山400 is on April 21st near 富士山(Mt.Fuji) and the distance is 400km.

- Masa

On May 9, 2012, at 8:47 AM, Michael Slater wrote: