Key Facts
• Sweet potatoes were designated as a ‘decisive resource’ during WWII.
• Japan increased sweet potato production for fuel and food from 1927.
• 1940 production target: 4.8 million tons; 1945 target: 9.63 million tons.
• Actual production reached only 74% (1940) and 40% (1945) of targets.
• Sweet potatoes were used to produce anhydrous alcohol for military fuel.
• Wartime rice shortages led to sweet potatoes becoming a staple substitute.
• 1941: ‘Sweet Potato Distribution Control Regulations’ banned free sales.
• Post-war food shortages persisted, termed a ‘national food crisis.’
• Sweet potato varieties like ‘Okinawa 100’ were developed for higher yields.
• Kawagoe, a major production area, shifted to high-yield varieties during the war.
• Sweet potato-based dishes, like ‘sweet potato porridge,’ were promoted.
• Experts highlighted the undervaluation of sweet potatoes in modern times.
• A 2025 event in Kawagoe discussed sweet potato history and wartime roles.
• Participants shared personal memories of sweet potato consumption during WWII.
Summary
During WWII, sweet potatoes became a critical resource in Japan, serving as both a fuel source and a substitute food amid severe rice shortages. Production was ramped up, with targets reaching 9.63 million tons by 1945, though actual yields fell short. Sweet potatoes were processed into anhydrous alcohol for military use and distributed as a staple food under strict regulations. Post-war, food shortages persisted, and sweet potatoes played a vital role in sustaining the population. Varieties like ‘Okinawa 100′ were developed for higher yields, though taste and quality varied by region and cultivation methods. A 2025 event in Kawagoe, a key production area, revisited this history, emphasizing the importance of re-evaluating sweet potatoes’ role in Japanese culture. Attendees shared wartime memories, reflecting on the hardships and resilience tied to this humble crop.
