Photo/IllutrationThe battleship Yamato during its sea trials in 1941 (Provided by the Yamato Museum)


The behemoth battleship Yamato was dispatched on its suicidal mission to Okinawa in 1945 because of a naval officer's misunderstanding of a question posed by the emperor, according to a newly disclosed document.  

The Yamato was sunk by U.S. carrier-borne aircraft on April 7, 1945, as it sailed toward Okinawa where its commanders were ordered to beach the vessel and use its mighty arsenal as a gun battery. 

More than 4,000 sailors, equivalent to the total fatalities linked to kamikaze suicide air attacks, were killed in the desperate maritime operation toward the end of World War II.

As 2025 will mark the 80th anniversary of the Yamato’s sinking, a previously unknown record was unearthed by The Asahi Shimbun to shed light on why the reckless plan had been put into action.

The latest finding reinforces the possibility that the Yamato’s one-way mission to Okinawa was abruptly hatched on April 4, 1945, as Emperor Hirohito, posthumously known as Emperor Showa, “asked” a naval executive officer about the status of available surface vessels.

The operation was finalized on the next day, April 5, 1945.

It had previously been believed that the emperor asked that question on March 29, 1945, one week before the decision was made to launch the special mission, according to the conventional, widely accepted theory.

“Such a large-scale mission was developed too hastily, indicating how grave the impact of the emperor’s comment on the navy was,” said Kazushige Todaka, director of the Yamato Museum in Kure, Hiroshima Prefecture, who studies historical facts about the Imperial Japanese Navy.

He continued, “Excessively concerned with doing what they thought the emperor wanted and upholding the navy’s honor, officers seemingly rushed to reach the decision. This could also explain the shoddy implementation of the plan.”

UNKNOWN RECORD

The discovery is based on the recollection of Sakuo Mikami (1907-1996), who once served as part of the Combined Fleet’s staff.

His account was recorded in 1988 during a gathering of the Suikokai group for exchanges among personnel from the Imperial Japanese Navy as well as the Maritime Self-Defense Force.

While the record was kept inaccessible to the public, it was checked and heard with the permission of his bereaved family.

Mikami's recollection shows that he received a phone call from staff officer Shigenori Kami at the Combined Fleet’s headquarters on April 4, 1945, during Mikami’s business trip to Kanoya, Kagoshima Prefecture.

Kami told Mikami that the “head of the Navy General Staff was asked if the navy had any ships left when he notified His Majesty the Emperor (of a special aviation operation above Okinawa).”

Referring to the navy general staff head’s embarrassment when leaving, Kami reportedly stated the specialized mission “must take shape as soon as possible given this.”

The emperor’s question about vessels had previously been believed to have been asked on March 29, 1945, in what is currently known as “Document Senkan Yamato” (Documentary on the battleship Yamato).

The publication was released in 1975 by such parties as writer Mitsuru Yoshida, who is well known for his book “Senkan Yamato no Saigo” (The last moment of the battleship Yamato).

The documentary title insists that the emperor’s question had only an indirect influence on the development of the Yamato’s last mission.

This theory reportedly derives from “Taiheiyo Senso Nihon Kaigun Senshi” (Japanese navy’s record on the Pacific War), which was compiled by the No. 2 bureau of demobilization. Only ceremonial exchanges are illustrated and the question about ships is not included in the material.

In the meantime, Mikami’s memorandum on the “developments in the Yamato’s special operation” that dates to 1970 specifies that the phone call from Kami over the emperor’s inquiry came in “April.” What day of the month it was made remains unclear in it.

Some considered the word “April” to be a typographical error or a misprint for “the 4th,” concluding that the emperor asked the question that day. It was confirmed through the recently uncovered recorded account that Mikami actually said “the 4th.”

UNSATISFACTORY PLAN HATCHED

On April 6, 1945, Mikami, who was not involved directly in the development of the specialized mission at the time, visited Seiichi Ito, commander in chief of the No. 2 fleet, who would be responsible for the envisioned convoy to Okinawa.

Working with chief of staff Ryunosuke Kusaka, Mikami tried to convince Ito to utilize the Yamato on the mission.

Hearing Kusaka suggest that Ito should die “ahead of others in line with the policy of ‘100 million people’s total suicidal attack,’” Ito asked “what is the campaign’s purpose” and “how much do you expect from us.”

In response, Mikami said they were “considering beaching it (the Yamato) on Okinawa in the end to launch a desperate attack.”

Ito replied that he “understood well that what was required was a battle style that goes against standard war strategies” and ended their conversation.

The following day, April 7, 1945, the Yamato was sunk by a fierce onslaught by U.S. airplanes as it sailed toward Okinawa.

When Mikami afterward saw a surviving executive officer from the special attack convoy in Sasebo, Nagasaki Prefecture, he received “all sorts of insults and curses” there.

In the recording, Mikami pauses for a long time, at a loss for words, and goes on to say that the crew on “the Yamato were extremely dissatisfied with this operation, as we forcefully pushed for it in hindsight.”

NOT WANTED BY EMPEROR

Akira Yamada, a history professor at Meiji University, said the emperor was clearly nervous and distraught when the U.S. military landed on Okinawa on April 1, 1945, to seize key airfields within striking distance of the mainland. 

Hoping to negotiate a peace after dealing a crushing blow to the U.S. forces, the emperor sternly questioned a senior Imperial Japanese Army official on April 3, 1945, on why “local troops are not going on the offensive.”

If the emperor’s question about ships was raised around that time amid the worsening situation, Yamada noted that the inquiry may reflect his intention of utilizing the Yamato and other remaining surface vessels for the battle in an effort to turn the tide of the war. 

“The emperor would like to see positive results via the deployment of the Yamato,” surmised Yamada.

After the battleship’s sinking, the emperor asked on April 30, 1945, whether “the Yamato and other vessels were properly utilized.”

The Imperial Japanese Navy described the Yamato's operational guidance as “inappropriate,” remarking that the “beaching mission was conducted too hastily, lacking careful preparation under a rushed plan.”

“It (this episode) indicates the emperor did not even imagine that the battleship would be deployed on such an unfruitful desperate mission,” Yamada said.