Hoover Institution (Stanford, CA) — The Hoover Institution Library & Archives has acquired the wartime journals of Captain Ichirō Shimoda, an officer in the Imperial Japanese Navy who served as a naval aviator during the Second World War. Captain Shimoda participated in several major Pacific War operations, including the attack on Pearl Harbor, and was killed in action during the Battle of Tinian in 1944.
The journals span the years 1939 to 1944 and document Shimoda’s naval service, including assignments aboard the battleship Nagato and the aircraft carrier Hiryū. Written primarily as a professional record of duty, the entries provide detailed firsthand accounts of naval aviation operations and carrier warfare during the early and middle years of the Pacific War.
Among the engagements described are preparations for and participation in the Pearl Harbor attack, operations of the Second Carrier Division’s dive-bomber unit, the bombing of Wake Island, and the sinking of the British aircraft carrier HMS Hermes. The journals are notable for their precision and technical clarity, often accompanied by hand-drawn maps tracing battle formations and attack outcomes. When available, these maps are supplemented by aerial photographs, offering rare visual insight into Imperial Japanese Navy operational planning and execution.
While the journals are largely formal in tone, reflecting Shimoda’s role as a professional officer, they occasionally reveal a more personal and emotional dimension. One particularly striking entry was written on December 6, 1941 (Japan time), on the eve of the Pearl Harbor attack:
0900 (Recorded in Japan time)
Signal received from the flagship:
“The rise or fall of the Empire rests upon this single battle. Let every man exert himself with utmost effort.”1400
All hands assembled
Imperial Rescript conveyed
Admiral of the Combined Fleet’s address conveyed
Air group commander’s addressAfter sunset, second alert formation
(This will likely be the last time I write with my pen. From 12/8 onward, I shall write from hell.)
This passage captures both the gravity of the moment and the psychological weight borne by participants on the eve of one of the most consequential military actions of the twentieth century.
The Shimoda journals add a significant primary source to Hoover’s holdings on the Pacific War, offering scholars a rare perspective from within the Imperial Japanese Navy’s carrier air forces. This collection is especially valuable for scholars of military aviation, naval doctrine, and intelligence, among other areas. As with many materials preserved at Hoover, these documents contribute to a deeper, more nuanced understanding of global conflict by preserving voices from all sides of history.
