Being vegan in Japan is very possible, but requires learning a few words and phrases. Here is a short list of kanji, phrases, words to remember, when ordering food or translating items on packacking.
I know this list is quite long and the kanji aren't all easy to remember, but the more you translate the more you'll learn to recognize them. An obvious great way to avoid animal products is to not buy pre-packaged foods, but that is not always possible, so here goes:
Without fish, meat, eggs and milk please.
Is there any vegan food?
Vegetables only please.
Is there any egg in this?
Is there anything on the menu that doesn't have meat?
I am vegan.
I don't eat meat.
Vegan onigiri exist in Japan, it's only a question of reading the tags and identifying them properly. Here is a list of the ones to look for:
It's never easy to find good vegan ramen, but it does exist! I have two recommendations of places in Tokyo that I've tried:
This tuber is a good egg alternative when baking both sweet, and savoury dishes. When grated, it becomes slimy and thick and can be used as a binding agent in many recipes. It imparts little flavour. It is perfect for okonomiyaki.
Fu, wheat gluten or seitan, is widely used as a meat alternative. It has a chewy stringy texture, and can be made into many shapes. You can buy fu in japan, it looks like dry bread cut into small discs, otherwise you can buy gluten flour and make your own. It is also possible to extract the gluten from the flour, but it requires a lot of water and time. You can use fu to add bulk to soups, and the flour can be used to make sausages and a variety of faux-meats.
A potato that can be processed into a jelly-like substance, it can be used to make faux-sashimi and is delicious with soy sauce and wasabi. It is very low calorie, and high in fiber.
Kanten, or agar agar, is made from red edible seaweed and can be used instead of gelatin in jelly-desserts. It can also be used to make faux-cheese.
In most cafes, cow's milk is more prevalent. You'd think that in Japan soymilk would be widely adopted as a drink but in truth it's used primarily in cooking. Some cafes offer soymilk, but like in other countries they'll sometimes charge you extra for it.
If you walk up to a vending machine that sells canned coffee, you'll see many varieties but almost all have milk in them, all, except coffee labelled as "black" like "Boss black coffee". Drinking black coffee is always a safe bet.
Black chocolate isn't true black chocolate, as it always has milk powder in it. I've yet to find a Japanese brand that doesn't.
When buying pre-packaged granola or cereal, be careful because they often contain milk products (even if isn't clearly visible).
Some convenience stores sell snacks and have little illustrations on the front that tell you which allergy-prone item is present. Most have milk in them, but sweets like karintou do not.
In some restaurants, ordering a dish called "Yasai kare" or "Vegetable curry" doesn't necessarily mean there won't be meat in it, they sometimes add it anyway. When ordering it's always better to ask if there is meat or fish in it, I've been burned before.
Buying bread that doesn't have added milk, egg or butter is nearly impossible. Bread that doesn't have this do exist, but finding them requires some patience as this article attests.