The "Hyakumanbunnoichi Kōkūzu" is a map collection produced between 1939 and 1944, covering strategic areas in Northeast Asia, including Sakhalin, Primorski Krai, Manchuria, Korea, and central and southern Japan. With a 1:1,000,000 scale (1:1,000,000 kōkūzu), these maps meticulously chart air routes, roads, and urban areas, reflecting the geopolitical importance of the region. Marked "Gokuhi" (confidential) and detailed with contours and spot heights, these maps were essential for strategic planning during East Asia's era of intense modernization and expansion (Cynthia Leng 2024).
