Hakase no aishita Suushiki


The Professor's Beloved Equation


Interesting for fans of mathematics, especially number theory, and for fans of baseball.

Mathematical topics in the film:
(Square-)Root, imaginary numbers, faculty, friendly numbers, Prime numbers, perfect numbers, Napier number, Euler's equation.

Movie Data

Title: The Professor's Beloved Equation
Original title: 博士 の 愛した数式 Hakase no aishita Suushiki
Published: 2006
Length: 117 minutes

Director: Takashi Koizumi
Script: Takashi Koizumi, Yoko Ogawa
Music: Takashi Kako

Akira Terao - The Professor
Eri Fukatsu - Kyoko
Takanari Saito - Root as child
Hidetaka Yoshioka - Root as adult
Ruriko Asaoka - The widow


The Housekeeper and Professor is a novel from 2000. It was published in August 2003 by Shinchosha. The story revolves around a mathematician, "the professor", who suffered brain damage in a traffic accident in 1975. Since then he can only keep the memories of the last 80 minutes. The film tells of his interactions with a housekeeper and her son "Root". The professor shares the beauty of the equations with them.
The novel received the Hon'ya Taisho Award and was made into a film in January 2006. After being published in paperback in December 2005, one million copies were sold in two months. A record for Shinchosha paperbacks.

The acting people

The Professor
is 64 years old and a former university professor specializing in number theory. He loves math, children and the Hanshin Tigers. After a car accident at the age of 47, he can only remember 80 minutes. He stores important information on notes that are attached to his suits everywhere. He keeps baseball cards and other important memories in a cookie jar. He has trouble interacting with other people and the habit of talking about numbers when he doesn't know what else to say.

The Housekeeper
of the professor is a single mother. She was hired by the professor's sister-in-law. She is the tenth housekeeper in a row. At first, she feels frustrated because the professor is only interested in mathematics. But through the friendliness of the professor, she begins to show respect and affection for him. A relation to the professor comes when he discovers that her birthday is February 20 (220), which is a friendly number of 284. This number is stamped on the underside of his watch, which he received as a prize for a work on transcendental number theory.

is initially ten years old. He is the housekeeper's son. The professor calls him "root" because the top of his head is flat like a square root symbol. He is an avid fan of baseball as well as of the Hanshin Tigers just like the professor. The professor is like a father to him because he is the first fatherly figure in his life. He grows up and eventually becomes a math teacher at a junior high school.

The widow
is a sister-in-law of the professor. First she fires the housekeeper for disregarding the employment contract rules. She accuses the housekeeper of wanting to sneak money from the professor. The professor wrote down Euler's formula during the confrontation conversation. So the widow immediately accepts the housekeeper and root again. It is implied that the professor and his sister-in-law had a relationship a long time ago.