Sam, I can not reply to your post via PM. I get the following error:
"Sorry no user was found."
So, I will post the answer here temporarily. I got the Evernew bottle at Victoria. It is a large sports store chain. Maybe they have a location near you in Kyoto, maybe not. A bilingual local who is involved in sports, or a taxi driver would definitely know.
Here's their homepage
However, I do not recommend Evernew plastic bottles, mine burst after about 10 uses. I recommend Platypus or Nalgene collapsables. But anyway, you came all this way, so buy one and take it home. Maybe mine was just a fluke.
While here, you might want to get some Japan-only Snowpeak stuff, like the 220ml titanium cup, etc.. Now THATS a small cookset when paired with a mini-bull.