If the United States held it, American forces would gain airfields, anchorages, and staging areas near Japan itself.
Japanese leaders understood the danger.
The defense of Okinawa therefore involved far more than the soldiers dug into the island.
Japan prepared a major air response called Kikusui, or “Floating Chrysanthemum.”
Kamikaze aircraft would attack the American fleet in great numbers.
On April 6 and 7 alone, the first major Kikusui attack involved hundreds of Japanese aircraft. NHHC records 355 kamikazes and another 340 aircraft used in conventional strike or escort roles during the larger operation.
American ships paid heavily.
Destroyers and other vessels around Okinawa faced repeated suicide attacks.
The attacks damaged or sank numerous ships and caused substantial American casualties.
Inside that enormous air operation was another idea.
Japan still had Yamato.
Someone decided she should go to Okinawa too.
The plan became Operation Ten-Go
The surface portion of the Japanese response is commonly known as Operation Ten-Go, or Ten-ichi-go, “Heaven Number One.”
Yamato would form the center of a Surface Special Attack Force.
The force contained ten ships:
Yamato.
The light cruiser Yahagi.
The destroyers Isokaze, Hamakaze, Yukikaze, Asashimo, Kasumi, Hatsushimo, Fuyuzuki, and Suzutsuki.
Vice Admiral Seiichi Ito commanded the force.
Captain Kosaku Aruga commanded Yamato.
Rear Admiral Keizo Komura commanded Destroyer Squadron 2 aboard Yahagi, whose captain was Tameichi Hara.
The language “special attack” carried grim meaning by 1945.
Japan had already institutionalized suicide attack methods.
Aircraft were being sent deliberately against ships.
Small boats and other weapons had been developed around the same idea.
The Yamato sortie belonged to that environment.
NHHC describes the planned mission clearly.
The force would sail toward Okinawa with very limited air cover. If it reached the American invasion fleet, it would attack transport shipping. Yamato and surviving escorts would then move toward Okinawa. Yamato was expected to beach herself and continue firing her guns until her ammunition was exhausted. Surviving crewmen would go ashore and join the ground battle.
This was not a normal naval mission with a planned return.
The ships were being sent into a situation from which Japanese leaders understood that survival was unlikely.
The U.S. Naval Institute later summarized the problem through Captain Hara's view of the plan. Hara regarded the sortie as “like throwing an egg against a rock.”
He went anyway.
Even Japanese commanders argued against the mission
The popular image of the final Yamato sortie sometimes presents every Japanese officer as willingly embracing a glorious death.
The documentary history is more complicated.
Vice Admiral Ito initially opposed the operation.
Several senior officers considered it militarily wasteful.
They understood exactly what American carrier aviation could do.
They also understood that Yamato's enormous antiaircraft battery could not replace fighter protection.
Japanese commanders had already seen Musashi destroyed under repeated air attack at Leyte Gulf.
Sending Yamato toward Okinawa without sustained air cover looked less like a naval operation than sacrifice.
NHHC describes the reaction among ship captains when details were explained on April 5 as approaching the closest thing to a mutiny in the wartime Japanese Navy.
The objections did not change the order.
A staff officer was sent to persuade Ito.
One later U.S. Naval Institute account preserves the appeal made to him:
“You are being offered a glorious way to die.”
The sentence reveals the gap between military practicality and the political culture surrounding Japan's final defense.
The operation went forward.
The fuel story is more complicated than the legend
A common version of the Yamato story says the ships received only enough fuel to reach Okinawa.
That description captures the suicidal character of the operation, but the actual fueling was more complicated.
The mission was planned as one-way in purpose.
Japanese fuel officers nevertheless loaded more fuel than the narrow written allocation might suggest.
There was enough fuel aboard for considerably more movement than a mathematically exact one-way voyage.
That extra fuel did not make the operation a conventional round trip.
The strategic plan still assumed that Yamato would not return after reaching Okinawa.
The difference matters because a dramatic story does not need a technically inaccurate fuel claim to show that the mission was desperate.
Its orders already do that.
The ships were expected to fight until they could no longer continue.
Yamato sailed on April 6
The force left Tokuyama on April 6, 1945.
Men aboard the ships knew they were heading toward an extraordinary operation.
Some personal papers were removed.