Poo-pooing Deviation Value (偏差値)

Very intelligent discussion with my mentor Hiro

Masahiro (Hiro) Nakagawa
3 min readOct 22, 2021


Coaching from Sub Zero — fighting against COVID-19 with Zoom / Autumn-Winter 2021–22 / Week 5

Credit; Hiro Nakagawa @ Acqualine, Tokyo

Last weekend was an annual Takeuchi Zemi Golf and I am honored to be a chauffeur for Hiro Takeuchi sensei and his wife Nobu-san. 50 miles drive to the golf course are always my precious moment with lots of updating, sometime at very private topics. At some topic of education, Takeuchi sensei asked me, simply,,

“Hiro, how do you calculate Deviation Value (偏差値) ?”

Takeuchi Sensei is lifetime tenure Professor of Harvard Business School and Chancellor of International Christian University (ICU, Tokyo), and this question is not to be expected to answer the formula of;

(Your Score — Average Score) / Standard Deviation x 10 + 50

This protocol is at very high level of discussion on how Japanese education system are too closed. In Japan (and in Korea and at some Chinese region), Deviation Value is a kind of “religion” to evaluate the school and students domestically. Already Japan’s tutoring industry are at US$ 20 billion value and one of the largest industries in my country. But this “Deviation Value” can work only with closed Japanese educational system and made hierarchy. Indeed, we have SAT in the US, but we count on only “score” and we evaluate the other elements of logical thinking, presentation, social activities; which had a larger part to be able to join the excellent collages.

Hence, Deviation Value is only a tool to protect the closed educational system, but can not compete globally. Takeuchi sensei and I strongly believe that this “religion” of Deviation Value is one of the core issues for Japan’s educational to be isolated from the global market.

Currently we see many good cases which escape from this “religion” and try to open to global. Thanks to many good encounters, I will shift my base from Kyoto to Yamanashi from next Spring (as a Professor (Non-Tenure) Yamanashi Gakuin University), I will extend this protocol to materialize at the new base. My Nakagawa Zemi had 3rd in Kyoto, and from 4th, we will start in Yamanashi, commutable from Tokyo, and all Alumni of Nakagawa Zemi will help me there.

As I always mention, education is one of the largest issues in Japan and I will continue to implement the exercise how we should survive in this global market, and let the students capitalize one.

Hiro Takeuchi Sensei at his Lab, 1986

This is one of my favorite photos of Takeuchi Sensei when I joined his class in 1986; His smile always guides us and I will try to “pay forward” what we learn from him, to my apprentices.

Class, follow us!



Masahiro (Hiro) Nakagawa

Street Economist / Strategist, Founder of Nakagawa Zemi/Lab