Author and operator
Koki Saito is responsible for writing and editing the articles and checking formulas and solutions. SubController LLC operates the website and handles inquiries.
About the author
I am a physician and a graduate of the University of Tokyo Faculty of Medicine. The Japanese name of this blog refers to a medical student because I started it while I was still a student.
I write about entrance-exam mathematics using the experience I gained preparing for the University of Tokyo. In my own entrance exams, I received full marks in Center Test mathematics and scored 104 in the University of Tokyo second-stage mathematics examination.
My aim is to provide explanations that remain useful even for students preparing for demanding examinations. The articles use typeset mathematics and worked examples to show both how to choose a method and how to write a solution.
What you will find here
The Japanese site covers algebra, geometry, probability, sequences, calculus, past University of Tokyo papers, Common Test mathematics, and study resources. The English collection covers integer problems, probability recurrences, parameter-dependent equations, swept regions, and circle inversion.
Editorial approach
Articles explain definitions and formulas alongside examples, applications, and common pitfalls. Past-paper discussions also consider difficulty and the decisions involved in constructing an answer. The solutions are the author's own explanations, not official University of Tokyo solutions.
Older articles are corrected when errors in formulas, formatting, or examination information come to light. Reader feedback helps improve these explanations. Please contact us if you find an error, would like a clarification, or have a problem you would like explained.