The customs at that time were recorded in some ancient books in Japan. In addition, the fuel used by Japanese women to dye their black teeth is iron slurry or black water from tea wine vinegar. Because at that time, the Japanese thought it was beautiful to dye their teeth black, which could keep their teeth clean, so many women in Japan did it. In addition, according to the description of some ancient books, we can see that Japanese women can't even get married if they don't shave their eyebrows and don't dye their teeth. This shows that the popular aesthetics in Japan at that time was like this.
In addition to imitating women in the Tang Dynasty, many Japanese men also dyed their teeth black, especially some warriors and ministers. This custom lasted for a long time before it was abolished, so it was just a previous custom. Regarding the behavior of ancient Japanese women shaving their eyebrows, people think that they may be imitating the relevant practices of women in China and Tang Dynasty, because women in Tang Dynasty in China like to shave their eyebrows and then draw their favorite shapes with eyebrow pencil.
Aesthetic appreciation At that time, women in the Tang Dynasty liked thrush, especially girls with thick eyebrows, thin eyebrows and arch eyebrows. Many netizens said that Japanese women may have shaved their eyebrows after studying the Tang Dynasty, but most Japanese women don't brush their eyebrows after shaving them. In fact, these are very old customs, and there is no need to look at them from a modern perspective. After all, these are all previous aesthetics.