Overview
- The explosion occurred during live-fire training on April 21, 2026, at the Hijuudai range and killed three turret crew members while seriously injuring the driver.
- Investigators conclude that combustion residue or debris left in the 120 mm gun barrel likely ignited a follow-on round rather than human error causing the detonation.
- Examiners also found evidence the breech/closure did not fully seal, which allowed blast effects to enter the turret and fatally injure personnel inside.
- The Japan Ground Self-Defense Force set up an accident investigation committee at Western Army headquarters in Kumamoto and plans to publish a formal report by year-end.
- Live-fire training remains suspended across affected units while the ministry evaluates ammunition modifications, procedural fixes, and equipment checks that could delay a return to full drills.