China and Vietnam are two neighboring countries that are located in Southeast Asia. Like any neighbors, they have a relationship that can be friendly or not so friendly.
A long time ago, China ruled over Vietnam, but Vietnam didn't really like that very much. So, Vietnam fought against China and eventually won their independence. Since then, China and Vietnam have had a bit of a rocky relationship.
Today, China is much bigger and more powerful than Vietnam, and this makes Vietnam a bit nervous. While they trade with each other a lot, Vietnam is always worried that China may try to take over their land again. That's why sometimes the two countries get into arguments over things like a small island in the South China Sea that both countries claim as their own.
Despite their disagreements, China and Vietnam still trade a lot with each other. They sell things like electronics, clothes, and food to each other, which helps their economies. But sometimes, when one country doesn't like something the other is doing, they may put tariffs or taxes on those goods to make them more expensive.
Overall, China and Vietnam have an interesting relationship because they both have a shared history, but they also have some tensions because of their differences in size and power.