Hi David,
I'm in Kyoto and there's a
Yodobashi Camera right in front of the station that carries a lot of film -- not nearly as much as in the Osaka and Tokyo stores -- but they do carry Ilford Delta in 120 and 35mm, so that shouldn't be a problem. Even if they are out of stock, Osaka is only a 30-minute train ride away, and the Yodobashi Camera (and BIC Camera for that matter) are much stocked much better than in Kyoto. Same goes for paper. In Kyoto there is fiber paper, mostly Fujifilm, Ilford, Foma, Bergger, and Oriental, and I think they carry it in 30x40 (not all brands though). There tends to be more variety in the smaller sizes here. Again, Osaka will have a better selection, especially for non-Fujifilm paper and larger sizes. I've never seen Tetenal chemicals in Japan, although they do carry Kodak and Ilford chemicals (for paper and film), and a larger comparable selection of Fujifilm chemicals (which work just as well but don't have English translations). It is possible to buy some raw chemicals in the store as well, like potassium ferricyanide, borax, potassium bromide, etc. (most of them come with an English translation of the Japanese characters so you know what you're buying).
Hope that helps. Let me know if you have any more questions.