Some parts have marks or slight lines drawn on them, such as problem numbers. There are a total of 7 books. The red books are from 1991 to 2015. I think it's difficult to get old past exam questions, so I recommend them. The yellow book is the 2020 version and is a good book for understanding Kyoto University mathematics well. I also have other reference books related to Kyoto University and university entrance exams, so please take a look.