Gluten-free in Japan

After all these years studying Japanese and wanting to get to Japan, now that it seems I may achieve my goal sometime in the near future, my main worry is food! I have been looking into it, and really have got nowhere. I know at least that Tamari soy sauce you can buy here in Spain (although quite difficult to find) is ok, but it seems to be Japanese don't really know what coeliac disease is... All I found on a forum is someone who read there were under 30 diagnosed Japanese coeliacs in 2006 (or was it 2005?). And the coeliac disease entry in the Japanese Wikipedia doesn't really have any links to anything useful in Japanese! I have found various posts in forums enquiring about where to eat gluten-free in Japan (especially in Tokyo), no-one seems to really have come up with a clear answer... except one Japanese person who said you can shop gluten-free in Natural House (and I'm afraid I'd already come to that conclusion thanks to an advert on a webpage... I'd be lost without Google ads!). The only problem is knowing what you can buy, as if it wasn't hard enough in your own language... luckily here's a video on youtube about forbidden ingredients....

Dietary Specials

This is a brand which I really haven't seen much down here, since most of my food comes from the same supermarket, but as I say, Mercadona doesn't actually make specifically gluten-free products, they just mark the products which are gluten-free. Right now Dietary Specials is actually the only gluten-free make I can think of which is sold there (at least in my local one, don't know about Mercadonas in larger cities). And I must admit I think I've only tried their Corn Flakes, but, as someone who has grown up being a Corn Flakes addict, I must admit I'm really chuffed with this gluten-free version :). On the DS webpage they have a store locator, although I can't find Mercadona in it, so I assume it leaves out all supermarket chains. I just wish I could try those ice-cream cones...