Kyūji is a word from Japan that means "emergency". When something bad happens and people need help right away, they call kyūji.
For example, if there's a fire or someone gets hurt, people can call kyūji and firefighters or doctors will come to help. It's like a secret code that lets people know they need assistance quickly.
Just like when kids have an emergency and need to call 911 in America, people in Japan use kyūji to get help in a hurry.