Chashi is a traditional Japanese castle that is built on top of a hill or mountain. It is like a big, strong house where the leader of the castle, called a daimyo, lives with his family and warriors.
The castle is built in a special way to make it very difficult for enemies to attack or to break down the castle walls. The walls are made from big blocks of rock or stone or sometimes even lava, and they are very thick and high.
Inside the castle, there are many different rooms and spaces for different purposes like sleeping, cooking, eating, and training for battle. The rooms are designed to be comfortable for the daimyo and his family, but also to be protected in case of an attack.
There are also special areas in the castle, like lookout towers and gates, where guards can keep a close eye on the surrounding area and make sure enemies don't get too close.
In summary, chashi is a huge castle that is built to keep the daimyo and his people safe from enemies. It is protected by thick and strong walls, lookout towers, and gates, and has many different rooms and spaces for different purposes.