Tofu in China
November 2016 - The first people to write about tofu were writers from the Song Dynasty in China, about 900 AD. Those Song Dynasty writers thought tofu had been invented by a Taoist prince of the Han Dynasty, Liu An, about 100 AD, but tofu might be even earlier: the Greek historian Herodotus, in the 400s BC, describes people far to his East who "speak a language of their own" and might be Chinese. He says they eat "a fruit like a bean," and that from those beans they make a thick black liquid - is it soy sauce? - and solid cakes which they eat instead of meat, which could be tofu. He thinks this is somehow mixed up with milk, maybe because the mashed soybeans look like milk.
Tofu seems to have been invented by Taoists, but soon it became very popular with Chinese Buddhists, who were strict vegetarians and didn't eat meat or milk. Tofu can taste something like meat, and it has a lot of protein like meat, but it is made out of soybeans.
To make tofu, you take soybeans and soften them by soaking them in water. Then you squash them into a soybean mash - that mixes with the water to make bean milk. Then you add acid (vinegar or citrus juice) to the bean milk, and that makes it coagulate (clump together) into something that looks like plain yogurt, which is tofu.
How to make tofu
You make cheese out of milk just the same way, and probably people got the idea to make tofu from making cheese. Tofu was a way to make something like cheese for people who didn't have cows or sheep, because there were not very many cows or sheep in China.
Tofu can be cooked lots of different ways. You can fry it, or bake it, or eat it raw.
The Chinese god of war, Kuan-Ti, was supposed to have been a tofu-seller when he was a child (before he became a god). But Kuan-Ti was a child during the Han Dynasty, so either tofu was invented earlier than most historians think, or Kuan-Ti must have been selling something else.