Satō Tetsutarō's hypothetical enemy: the United States as the imperial Japanese Navy's most capable adversary, 1902-41

• Main Author: Au-Yeung, Justin Ho
• Other Authors: -
• Format: Thesis-Master by Coursework
• Language: English
• Published: Nanyang Technological University 2023
• Subjects: Social sciences::Military and naval science::Strategy::Asia
• Online Access: https://hdl.handle.net/10356/168710
• Institution: Nanyang Technological University

Despite being dubbed the Imperial Japanese Navy’s (IJN) ‘most foresighted planner’, Satō Tetsutarō remains critically understudied in the scholarship of the IJN and its defence policy. This dissertation explores the following questions: How did Satō’s hypothetical enemy concept manifest itself in Japan’s defence policy? How did that manage, or lead to war, with the U.S. at Pearl Harbour in 1941? It is argued that sustained perceptions of the U.S. as Japan’s hypothetical enemy existed for decades prior to Pearl Harbour. Satō posited that the best way for the IJN to provide national security was for it to tailor its defence policy and strategy against the most formidable hypothetical enemy. The process of setting a high standard would allow the IJN to expand its naval capabilities and simultaneously deter the hypothetical enemy from pursuing confrontation with Japan. This concept of deterrence ultimately failed when Japan realised it lacked the sufficient capability to match the United States Navy (USN), and therefore perceived it as necessary to launch a preventive strike. The strong emphasis given to capability factors in Satō’s concept meant that IJN planners were prejudiced to respond to their strategic problems with solutions that focused on increasing the IJN’s capabilities, no matter how unfeasible it became, with little regard for conflict mitigation and alternative strategies to be considered. The IJN’s obsession with comparative naval capabilities in their threat calculus ended up exacerbating IJN insecurities, paving the way for the attack on Pearl Harbour.