Okay kiddo, do you know what concessions mean? It is just like when mommy and daddy give you a treat or let you do something in exchange for something else.
In China, concessions were areas of land that were given to other countries (mostly European countries) to use for trading and business purposes in the late 1800s and early 1900s.
So, imagine if your room was given to your friend for them to play in, but they had to give you their toys in exchange for using your room. That's a concession.
China gave these concessions to the other countries because they wanted to increase their trade and boost their economy. These areas were mostly located in big cities like Shanghai and Tianjin.
However, sometimes the countries took advantage of these concessions and did things that were not good for China, like treating Chinese people unfairly or exploiting resources.
Eventually, after many struggles and conflicts, China succeeded in reclaiming these concessions and gaining control over their own territory.
So, that's what concessions in China were all about. It was like a trade-off where other countries got to do business in China, but China gained something in return.