The ancient chestnut mutton soup really has "sheep" and is indeed "soup". In the Tang Dynasty, the original chestnut mutton soup was made of mutton. But after it spread from China to Japan, because monks don't eat meat, they made it into the shape of sheep liver with red beans, Ge Fen and flour. The Japanese pronunciation of "liver" and "soup" is similar, so "sheep liver" is called "mutton soup" and became a famous refreshment when the tea ceremony was popular.
In the era of Toyotomi Hideyoshi, mutton soup with bean paste was the most popular. Japanese mutton soup is made of red beans, and later developed into different styles such as chestnuts and sweet potatoes. Adding a certain proportion of chestnut noodles to chestnut mutton soup is the fine product of mutton soup.
Sheep liver cake? Zhou Zuoren (published in August, 1957, selected from the last 49 pages of Collected Works of Tang Zhi).
A thing, produced in China, was shipped to a foreign country for four or five hundred years, and then brought back, but it looked different. This is true in all things, but it is especially obvious in things that have a preference for eating, such as the famous refreshment "mutton soup", which is the best example.
The name "mutton soup" is unknown, and it didn't appear in the market until it was copied in Beijing recently. This soup is not made of mutton, but a vegetarian dish. It is made of adzuki beans, refined with sugar, condensed into blocks and cut into long strips. So it should be called "bean paste sugar" and seek truth from facts.
However, this has always been written like this in Japan (because it is originally a Japanese imitation food), and they are also puzzled. Explain it. There is also a saying that this kind of bean paste candy was originally called sheep liver cake in China, because the color of the cake is almost the same, and it spread to Japan, and I don't know why it was mistakenly called sheep soup.
It's a pity that we can't find the classic of sheep liver cake in China, but it's hard to find out what kinds of snacks there are in the Tang Dynasty, so it's best to admit that this is a reasonable explanation.
The person who taught China's knowledge and technology to Japan was a Japanese monk studying abroad. Besides studying, they also pass some food. Sheep liver cake is the food brought back by these monks, and it became popular as a refreshment in the era of "tea ceremony" in Gregorian calendar 15 and 16 century.
One feature of Japanese culture is "simplicity", and it is also a trend in diet, so there are shops specializing in mutton liver cakes (mutton soup), just like there are specialty shops that make kelp (kelp).
As a result, "mutton soup" is very famous. It is pure bean paste, authentic, made of chestnuts or persimmons, and the side door is not heavy enough. When it comes to Japanese tea, "mutton soup" is always the first one to be put forward. I didn't know its ancestors were in China, but it's impossible to find them at present.
Recently, I checked the descendants of sheep liver cake in China market, and it is still called "mutton soup", but it has changed beyond recognition because it joined the team of western-style dim sum. It takes off "simple" special clothes and puts on fashionable clothes to make "cream", "vanilla" and various fruits.
I hope it will retain at least a pure bean paste with the fragrance of adzuki beans. If you cook for a long time, you can persist for a long time, but you can't recover. In fact, among all kinds of popsicles (called popsicles in Shanghai), there is a kind of adzuki bean made of bean paste, which means a little sheep liver cake, which is quite delicious. Why not use it to make a delicious food?