A mind map was a graphic thinking tool used to display and organize complex concepts, relationships, and information. It was originally created by the Japanese inventor Keigo Higashino in 1972, so it was also known as the "Guide to Keigo Higashino". Mind maps help people better understand and remember complex concepts by connecting a theme image with its related sub-theme images. Mind maps were originally used to help people organize books and papers, but over time, they were widely used in various fields, including art, design, business, science, and medicine. Now, mind maps had become a popular thinking tool that more and more people were learning and using.