The Imperial Japanese Navy (IJN) deemed the Mitsubishi J2M Raiden (“Thunderbolt”) fighter suitable to fight B-29 Superfortresses toward the end of World War II due to several key factors that matched the Raiden’s design and capabilities to the challenge posed by the American bombers.
1. High-Speed Interception:
The J2M Raiden was specifically designed as an interceptor rather than a traditional dogfighter. It had a powerful Mitsubishi Kasei 23 engine that gave it exceptional speed for a Japanese aircraft of its time, reaching over 370 mph (595 km/h). This speed was critical for climbing quickly to the high altitudes at which B-29s operated—often above 30,000 feet—where most Japanese fighters struggled to engage.
2. Heavy Firepower:
The Raiden was armed with a formidable array of 20mm Type 99 cannons, which were far more effective against the heavy, well-armored B-29s than the lighter machine guns used by many other Japanese fighters. Some versions even carried 30mm cannons, providing greater firepower capable of inflicting serious damage on the Superfortresses with fewer hits.
3. Robust Airframe:
Unlike the more agile but lightly built Zero fighter, the Raiden was designed with a more robust structure, making it better suited to withstand the stresses of high-speed dives and head-on attacks against the heavily armed B-29s. Its durability allowed it to engage in head-on passes and survive return fire from the bombers’ numerous defensive machine guns.
4. Altitude Capability:
The J2M Raiden was one of the few Japanese fighters capable of reaching the high altitudes at which B-29s typically operated. Its engine was equipped with a two-speed supercharger that allowed it to maintain power at higher altitudes, giving it a critical advantage over other Japanese aircraft that struggled to climb and operate effectively against the Superfortresses.
5. Interceptor Role Suited to Defensive Tactics:
By the late stages of World War II, Japan’s air strategy had shifted to a defensive posture, aiming to protect the home islands from relentless American bombing raids. The J2M Raiden, as a fast-climbing, heavily armed interceptor, perfectly matched this defensive mission profile. Its purpose was not to engage in prolonged dogfights but to quickly climb, attack the bombers, and break away.
6. Desperation and Limited Options:
Finally, the decision to use the J2M Raiden against B-29s was also driven by necessity. Japan’s industrial capacity was severely degraded by 1945, and few new aircraft designs could be produced in sufficient numbers. The Raiden, already in service, became one of the best available options for intercepting the high-flying B-29s.