One of the Imperial Japanese Navy’s dreadnought battleships, the Nagato-class Mutsu, ended mysteriously and dramatically on June 8, 1943. Anchored off Hashirajima near Hiroshima, it exploded, leaving no one of the 1,121 crew members and visitors on board alive. To this day, the exact cause of this event remains highly speculative.
Completed in the post-World War I period, Mutsu was a mighty warship. Her name comes from Mutsu Province. The career of this ship was remarkable in terms of having taken part in helping people during the Great Kanto earthquake of 1923. Although heavy modernization was done on the ship between 1934 and 1936, which included the changing of her armor and machinery, Mutsu was seen as an outdated battleship when World War II broke out.
Throughout the war, Mutsu saw little in the way of significant action. She was part of the force giving distant support during the Pearl Harbor attack and saw the Battle of Midway from afar, but was not involved in the fighting. Her only recorded operational use came at the First Battle of the Eastern Solomons when she fired four shells at an American reconnaissance aircraft.
On one fateful June day in 1943, when Mutsu was cruising for exercises, there were 113 flying cadets and 40 instructors on board. At 12:13 PM, her No.3 turret magazine exploded and she was split in two. The forward section capsized and sank, while the stern remained afloat for some hours before finally sinking.
Rescue efforts began immediately as nearby ships sped to save those who could be rescued. Of the 1,474 sailors aboard, all but 353 were lost and of those saved, only 13 were the cadets. The Japanese Navy was so shocked at the disaster that it immediately stated that the ship had not collapsed as the result of an enemy assault. It then labeled the event to be one of state secrets to prevent the loss of the momentum of the morale.
Preliminary findings have shown that the explosion likely was due to human error. Besides, the magazine of the ship also contained 16-inch Type 3 “Sanshikidan” incendiary shrapnel Anti-Aircraft shells, which in the past were known to cause fires in the Sagami arsenal. However, authorities attributed the incident to sabotage brought about by a seaman who was suspected of petty theft, who supposedly made a fire near the magazine to divert attention.
Nevertheless, this hasn’t been enough to convince some historians. They point out that the Japanese Navy might have wanted to cover up its possible negligence, given that Mutsu was an old ship that carried so much flammable material; a fire caused electrically, very close to the magazine, would have been enough to set the explosion.
The sinking of Mutsu remains both tragic and enigmatic in naval history. Whether caused by sabotage or an unfortunate accident, the disaster serves as a somber reminder of the perils faced by those who serve at sea.