FlyFisher (Japanese)
A wonderful magazine on Japanese fly fishing. Incredible photography and technical articles with outstanding detail and diagrams. All in Japanese but worth it for the pictures alone, and a lot can be gleamed from the article diagrams and pictures.
Amazon Japan
A source for Flyfisher Japan magazine and other books and magazines. It has an English version for browsing and purchasing. (Japanese)

(Click here for English version)
Jauce is an English interface and purchaseing/shipping service for Yahoo Japan. Yahoo Japan is used widely in Japan for second hand goods, including many fly fishing items.
Furai no Zasshi ("Fly Magazine")
A small format, fly fishing magazine. Not as sumptuous as Flyfisher but lots of cool things to look at. All in Japanese.