Official Profile
Nonfiction Writer Legal name: Mayumi Eiki
A Tokyo-based nonfiction writer covering international politics and security affairs. Author of Japan’s Nuclear Armament I: Technology and Cost, among other titles. Yui Sakaki is the pen name of Mayumi Eiki.
Yui Sakaki is the pen name of nonfiction writer Mayumi Eiki.
Her work focuses on security affairs, international relations, and military technology.
A graduate of Kobe University’s Faculty of Business Administration, she worked at a major trust bank and an international consulting firm before relocating to the United States. Drawing on analytical skills developed across finance, management, and technology, she writes nonfiction that favors verified, concrete conditions — technical, financial, legal, and diplomatic — over hurried political conclusions.
Her debut book, Japan’s Nuclear Armament I: Unknown Capabilities — Technology and Cost (Gogatsu Shobo Shinsha), examines the technical feasibility and cost of a hypothetical Japanese nuclear arsenal, approaching a debate usually framed by ideology through the lens of engineering and expense instead. Its sequel, Japan’s Nuclear Armament II: What Restrains the Power — Law and the International Order (Gogatsu Shobo Shinsha), examines the domestic and international legal frameworks that constrain Japan’s nuclear options — the Three Non-Nuclear Principles, the U.S.–Japan nuclear cooperation agreement, the NPT, the CTBT, IAEA safeguards, and Japan’s Atomic Energy Basic Act.
She is currently writing on AI, military technology, ethics, and philosophy.
Japan’s Nuclear Armament · Vol. 1
A fact-based inquiry into whether Japan could develop nuclear weapons — examining material science, engineering constraints, and realistic cost envelopes.
Japan’s Nuclear Armament · Vol. 2
From the Three Non-Nuclear Principles to the U.S.–Japan nuclear agreement, the NPT, IAEA safeguards, and the CTBT — the legal and institutional hurdles standing in the way of Japanese nuclear armament, examined fact by fact.
Cover images are placeholders pending final artwork. Japanese-language book detail pages are available at yuisakaki.com/ja/books/.
Official information about Yui Sakaki is published through this site and the following official accounts and publisher pages.
“Yui Sakaki” is the pen name used by nonfiction writer Mayumi Eiki for her writing. This site is her official website.
Her publisher, Gogatsu Shobo Shinsha, along with Amazon and Hanmoto.com, list both her pen name and legal name in author credits.