The mastering phenomenon

Mastering used to be called seion, or “regulating sound,” in Japanese, and that’s pretty much what it literally is. That label was used at a time when the goal was, for example, to regulate the volume of an album tune and to reduce noise and control the sound quality. Time flows, the world changes, and Kotaro states, “I will further polish these mixed sounds.” He takes great pride in his work, which has so gained in significance and importance that he would like to call it to’on, or “sharpened sound.”
The question is what to sharpen, and how. “Elevating the delightful parts,” in other words, building on strengths. This is similar to how, in the world of sports, Western coaches often praise their players. The idea goes back to his long experience in the UK and the US. However, he’s not simply an optimist. “It takes dozens of hours, hundreds of hours, to get to the mastering stage–if you go back to writing the song maybe several years–and in this profession you could potentially let all that effort go to waste.” He has never forgotten this heavy pressure and a strong sense of responsibility.
Kojima also actively suggests ideas, which has gained him immense trust. As Franz Kafka said: “In relationships without trust, whatever you say is meaningless.” Everything is built on trust. He is particularly strong in the areas of rock and R&B, though his understanding of to-on is also highly praised in other genres as extraordinary for a Japanese person.


He traveled to England at 18, and then lived in the United States for six years beginning in 1988. He learned the basics of studio work at LA’s Ocean Way Studio, and after returning to Japan extended his career with over 20 years as a mastering engineer. His hobby is watching motor sports, and he occasionally appears in the race pits with a Paddock Pass dangling from his neck or watches Formula One as a Ferrari Team VIP. Recently he has surpassed the category of mastering and functions as sound supervisor at recordings or live concerts.

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