Japan is famous for its ubiquitous jihanki (vending machines). Drinks are of course the most common (with both hot and cold beverages available), with cigarette machines holding firm at second. When I first came to Japan, I was amused to see alcohol jihanki, which, unlike the cigarette machines, require no proof of age. You can occasionally find machines offering oden, ramen, bread and onigiri, and apparently there is a banana vending machine somewhere in Shibuya station! You've probably heard of the worn ladies' underwear machine- this is one I haven't seen myself, but as I have seen other racy items sold in vending machines, I don't doubt that it exists.
Some months back, while strolling the streets of lively Shimokitazawa, we came across vending machine that exclusively sells natto and related products. Even my koibito (sweetheart) was surprised to see it, so apparently the natto jihanki is a rarity.
For newbies, and those of you that don't live in Japan, I should probably explain what natto is, as I don't think I was acquainted with it before living here myself. Natto is basically fermented soybeans. It's usually eaten on rice, especially on a breakfast food, and sometimes can be found rolled up in sushi. Natto is inexpensive (about 40¥ per serving) and fantastically healthy, being high in protein and probiotics, but low in fat. To those familiar with natto, it has a lovely savory, beany, nutty flavor. To the uninitiated, however, natto's particular taste, strong (stinky cheese or stinky foot-ish) aroma, and slimy texture can be rather off-putting. I think it may be the texture that is the most challenging for westerners: in North America there aren't really any popular foods that have this texture. We associate sliminess with rotting garbage, pond scum, or mucous, not with something you'd want to eat. In Japan, however, neba-neba is a food texture category (like, say, chewy or crunchy) that includes yama-emo, okura, and nama-tamago (raw egg!). Though I'll admit that natto is an aquired taste (it took me a year of living in Japan before I started to like it), I think it's worth the effort and not-so-pleasant first tastes.
Natto is an excellent food for vegetarians in Japan (and elsewhere if you can find it!), with only one small drawback. Most packages of natto come with little packages of sauce that contain katsuodashi (bonito fish stock). If you are a pescatarian, or someone who is ok just discarding the sauce pack, this will pose no problem. If you're not cool with buying something with fish sauce in the first place, there are several specialty types of natto you should look for. They're not available at every grocery store, but if you check a few places you can probably find them! The first (and my favourite) is 黒豆 (black bean) natto, which comes with vegetarian friendly sauce. (Other brands may not be veg friendly, so scan the ingredients for かつお or カツオ or 鰹) You only get 2 little styrofoam packs for the price of the usual 3, but it's still quite reasonable. The second option is to buy sauce free natto, which is packed in a thin, rectangular paper container, wrapped again in plastic, rather than the little styrofoam squares.
Natto is most delicious with a little sauce mixed in (try the one in the black bean natto or throw in some shoyu / soy sauce), and lots of people like to sprinkle on some chopped green onions too. Make sure to mix up your natto until it is good and slimy too!