Buddhism is a religion that started long ago in a place called India. People who believe in Buddhism think it's important to understand the nature of suffering in the world and to work towards ending it. They also believe in something called karma, which means that your actions have consequences that can carry over into your future lives.
Buddhism became very popular in some other places too, including East Asia. This is a big part of the world that includes countries like China, Japan, and Korea.
In these countries, people practiced Buddhism in their own unique ways. For example, in China, people combined Buddhism with some of their own traditional beliefs to create a new form of Buddhism called Chan (or Zen in Japanese). This type of Buddhism focuses on meditation and experiences of sudden enlightenment, which means having a big realization about the nature of reality.
In Japan, Buddhism was also mixed with traditional beliefs, like the idea that all things have a spirit or soul. This helped people relate to Buddhism in a way that was more familiar and comfortable for them.
Overall, Buddhism has had a big impact on East Asia and continues to be an important religion for many people in the region.