Operation Ten-Go

Operation Ten-Go
Part of World War II, Pacific War
Yamato under attack. A large fire burns aft of her superstructure and she is low in the water due to damage from torpedoes.
Date 7 April 1945 Location Pacific Ocean, between Kyushu, Japan and Ryukyu Islands Result U.S. victory
Belligerents
United States	Japan
Commanders and leaders
Marc A. Mitscher	Seiichi Ito
Strength
8 carriers, 386 aircraft	1 battleship, 1 light cruiser, 8 destroyers
Casualties and losses
12 killed; 10 planes destroyed	3,700 killed; 1 battleship, 1 light cruiser, 4 destroyers sunk

Operation Ten-Go (天号作戦 ten-gō sakusen), sometimes referred to as Ten'ichigo (meaning Heaven number-one), was the last major Japanese naval operation in the Pacific campaign of World War II. The Japanese battleship Yamato, the largest battleship in the world, along with seven other Japanese warships, sortied from Japan on an intentional one-way mission to attack the Allied invasion forces at Okinawa. The Japanese force was attacked, stopped, and almost completely destroyed before reaching Okinawa by U.S. carrier aircraft which sank Yamato and five other Japanese warships.

The battle emphasized the aerial control that the U.S. had attained in the Pacific theater as well as the vulnerability of surface ships to aerial attack. The battle also apparently exhibited Japan's willingness to sacrifice large numbers of its people in desperate and suicidal tactics in an attempt to slow or stop the Allied advance on the Japanese homeland.

Background

By spring 1945, following the Solomon Islands campaign and Battles of the Philippine Sea and Leyte Gulf, the once imposing Imperial Japanese Navy's Combined Fleet was reduced to just a handful of operational warships and a few remaining aircraft and aircrew. Most of the remaining Japanese warships in the Combined Fleet were stationed at ports in Japan, with most of the large ships at Kure.

With the invasions of Saipan and Iwo Jima, Allied (primarily U.S.) forces began their campaign against the Japanese homeland itself. As the next step before a planned invasion of the Japanese mainland, Allied forces invaded Okinawa on April 1, 1945. In March, in briefing Emperor Hirohito on Japan's response to the expected Okinawan invasion, Japanese military leaders explained that the Army was planning extensive air attacks, including the use of kamikaze. The emperor then reportedly asked, "But what about the Navy? What are they doing to assist in defending Okinawa?" Now feeling pressured by the emperor to mount some kind of attack also, Japan's Navy commanders conceived a kamikaze-type mission for their remaining operational large ships, which included the battleship Yamato.

The resulting plan, drafted under the direction of the Commander in Chief of the Combined Fleet, Admiral Toyoda Soemu, called for Yamato and her escorts to attack the U.S. fleet supporting the U.S. troops landing on the west of the island. Yamato and her escorts were to fight their way to Okinawa and then to beach themselves between Higashi and Yomitan and fight as shore batteries until they were destroyed. Once destroyed, the ship's surviving crewmembers were supposed to abandon the ships and fight U.S. forces on land. Very little, if any, air cover could be provided for the ships, which would render them almost helpless to concentrated U.S. air attacks. In preparation for executing the plan, the assigned ships left Kure for Tokuyama, off Mitajiri, Japan, on March 29. However, in spite of obeying orders to prepare for the mission, Admiral Ito Seiichi, commander of the Ten-go force, still refused to actually order his ships to carry it out, believing the plan to be futile and wasteful.

Vice Admiral Kusaka Ryunosuke flew from Tokyo on April 5 to Tokuyama in a final attempt to convince the assembled commanders of the Combined Fleet, including Admiral Ito, to accept the plan. Upon first hearing of the proposed operation (it had been kept secret from most of them until now), the Combined Fleet commanders and captains unanimously joined Admiral Ito in rejecting it for the same reasons that he had expressed. Admiral Kusaka then explained that the Navy's attack would help decoy U.S. aircraft away from the Army's planned air attacks on the U.S. fleet at Okinawa. He also explained that Japan's national leadership, including the emperor, were expecting the Navy to make their best effort to support the defense of Okinawa. Upon hearing this, the Combined Fleet commanders relented and accepted the proposed plan. The ship's crews were briefed on the nature of the mission and given the opportunity to stay behind if desired—none did. However, new, sick, and infirm crewmembers were ordered off the ships. The ships' crews now engaged in some last minute, intense drills to prepare for the mission, mostly practicing damage-control procedures. At midnight the ships were fueled. Reportedly, in secret defiance of orders to provide the ships with only just enough fuel to reach Okinawa, the Tokuyama personnel actually gave Yamato and the other ships almost all of the remaining fuel in the port, although this probably still was not enough to allow the force to return to Japan from Okinawa.

Battle

Routes of the Japanese Yamato force (solid black) and U.S. carrier aircraft (dotted red) to the battle area (X).

On April 6 at 16:00 hours, Yamato, with Admiral Ito on board, the light cruiser Yahagi, and eight destroyers departed Tokuyama to begin the mission. Two U.S. submarines, Threadfin and Hackleback, sighted the Japanese force as it proceeded south through Bungo Suido but were unable to attack. However, they notified the U.S. fleet of the Japanese sortie.

At dawn on April 7, the Japanese force passed the Osumi Peninsula into the open ocean heading south from Kyushu towards Okinawa. They shifted into a defensive formation, with Yahagi leading Yamato and the eight destroyers deployed in a ring around the two larger ships, with each ship 1,500 meters from each other and proceeding at 20 knots. One of the Japanese destroyers, Asashimo, developed engine trouble and turned back. U.S. reconnaissance aircraft now began to shadow the main force of ships. At 10:00 hours, the Japanese force turned west to make it look like they were withdrawing, but at 11:30, they turned back towards Okinawa.

U.S. aircraft, such as this dive-bomber, begin their attacks on Yamato (center left). A Japanese destroyer is in the center right of the picture.

Around 10:00 this same day (April 7), the U.S. Navy began launching almost 400 aircraft in several waves from eleven carriers of Vice Admiral Marc A. Mitscher's Task Force 58 (Hornet, Bennington, Belleau Wood, San Jacinto, Essex, Bunker Hill, Hancock, Bataan, Intrepid, Yorktown, and Langley) that were located just east of Okinawa. The aircraft consisted of fighters, dive-bombers, and torpedo bombers. A force of six battleships (Massachusetts, Indiana, New Jersey, South Dakota, Wisconsin, and Missouri) supported by cruisers (including Alaska and Guam) and destroyers was also assembled to intercept the Japanese fleet if the air-strikes did not succeed.

Due to the Japanese force not having any air cover, the U.S. aircraft were able to set up for their attacks without fear of opposition from Japanese aircraft. U.S. attack aircraft arriving over the Yamato group, after their two-hour flight from Okinawa, were thus able to circle the Japanese ship formation just out of antiaircraft range, methodically setting up their attacks on the warships below.

The first wave of U.S. carrier aircraft engaged the Japanese ships starting at 12:30 hours. The Japanese ships increased speed to 25 knots, began evasive maneuvers, and opened fire with their antiaircraft guns. Yamato herself carried almost 150 antiaircraft guns. The U.S. torpedo airplanes mainly attacked from the port side so that, if the torpedoes mainly hit from that side, it would increase the likelihood of the target ship to capsize.

Yahagi under intense bomb and torpedo attack.

At 12:46 a torpedo hit Yahagi directly in her engine room, killing the entire engineering room crew and bringing her to a complete stop. Dead in the water, Yahagi was hit by at least six more torpedoes and 12 bombs by succeeding waves of air attacks. Japanese destroyer Isokaze attempted to come to Yahagi's aid but was herself attacked, heavily damaged, and sank sometime later. Yahagi capsized and sank at 14:05 hours. Her survivors, left floating in the water, could see the Yamato in the distance, still apparently steaming south and fighting attacking U.S. aircraft. However, in reality, Yamato herself was only minutes away from sinking.

During the first attack wave, in spite of intensive evasive maneuvers that caused most of the bombs and torpedoes aimed at her to miss, Yamato was hit by two armor-piercing bombs and one torpedo. Her speed was not affected, but one of the bombs started a fire aft of the superstructure that was never extinguished. Also, during the first attack wave, Japanese destroyers Hamakaze and Suzutsuki were heavily damaged and taken out of the battle. Hamakaze sank sometime later.

Yamato (upper right) dodging air attack during the battle.

Between 13:20 and 14:15, the second and third waves of U.S. aircraft attacked, heavily concentrating on the Yamato. During this time, Yamato was hit by at least eight torpedoes and up to 15 bombs. The bombs did extensive damage to the topside of the ship, including knocking out power to the gun directors and forcing the antiaircraft guns to be individually and manually aimed and fired, greatly reducing their effectiveness. The torpedo hits, almost all on the port side, caused the Yamato to list enough that capsizing was now an imminent danger. However, the water damage-control station had been destroyed by a bomb hit, making it impossible to counter-flood the specially designed spaces within the ship's hull to counteract hull damage. Therefore, at 13:33, in a desperate attempt to keep the ship from capsizing, Yamato's damage control team counter-flooded both starboard engine and boiler rooms, mitigating the danger, but also drowning the several hundred crewmen manning those stations, who were given no notice that their compartments were about to fill with water. The lives of those crewmen bought Yamato about 30 more minutes of life. The loss of the starboard engines, plus the weight of the water, caused Yamato to slow to about 10 knots.

With Yamato now proceeding more slowly and therefore easier to target, U.S. torpedo aircraft concentrated on hitting her rudder and stern with torpedoes in order to affect her steering ability, which they succeeded in doing. At 14:02, after being informed that the ship could no longer steer and was unavoidably sinking, Admiral Ito ordered the mission canceled, the crew to abandon ship, and for the remaining ships to begin rescuing survivors. Yamato communicated this message to the other surviving ships by signal flag, as her radios had been destroyed.

Yamato, afire, begins to capsize.

At 14:05 Yamato was stopped dead in the water and began to capsize. Admiral Ito and the captain of the Yamato decided to go down with the ship and refused to abandon her with the rest of the survivors. At 14:20 Yamato capsized completely and began to sink (30°22′N 128°04′E). At 14:23 she suddenly blew-up with an explosion so large that it was reportedly heard and seen 200 km away in Kagoshima and sent up a mushroom-shaped cloud almost 20,000 feet into the air. The explosion is believed to have happened due to the fires from the bomb hits reaching the main ammunition magazines.

Attempting to make it back to port, Asashimo was bombed and sunk with all hands by U.S. aircraft. The Japanese destroyer Kasumi was also sunk by U.S. carrier aircraft attack during the battle. Suzutsuki, despite her bow being blown off, was able to make it to Sasebo, Japan by steaming in reverse the entire way.

The remaining three less-damaged Japanese destroyers (Fuyuzuki, Yukikaze, and Hatsushimo) were able to rescue 280 Yamato survivors (out of a crew of 2,700), plus 555 survivors from Yahagi (out of a crew of 1,000) and just over 800 survivors from Isokaze, Hamakaze, and Kasumi. However, 3,700 Japanese naval personnel perished in the battle. The ships took the survivors to Sasebo.

File:Yamato3.jpg

Yamato explodes.

A total of 10 U.S. aircraft were shot down by antiaircraft fire from the Japanese ships; some of the aircrews were rescued by amphibious aircraft or submarine. In total, the U.S. lost 12 killed. Some of the Japanese survivors reported that U.S. fighter aircraft machine-gunned Japanese survivors floating in the water. This may have been a war crime or it may have been a legitimate attempt to protect downed U.S. aircrew who were floating in the water nearby awaiting rescue. Japanese survivors also reported that U.S. aircraft temporarily halted their attacks on the Japanese destroyers during the time that the destroyers were busy picking up survivors from the water.

During the battle, the Japanese Army conducted an air attack on the U.S. naval fleet at Okinawa as promised, but failed to sink any ships. Around 115 aircraft, many of them kamikaze, attacked the U.S. ships throughout the day of April 7. Kamikaze aircraft hit the Hancock, battleship Maryland, and destroyer Bennett, causing moderate damage to Hancock and Maryland and heavy damage to Bennett. About 100 of the Japanese aircraft were lost in the attack.

Aftermath

Ten-Go was the last major Japanese naval operation of the war, and the remaining Japanese warships had little involvement in combat operations for the rest of the conflict. Suzutsuki was never repaired. Fuyuzuki was repaired but hit a U.S. air-dropped mine at Moji, Japan, on August 20, 1945, and was not subsequently repaired. Yukikaze survived the war almost undamaged. Hatsushimo hit a U.S. air-dropped mine on July 30, 1945, near Maizuru, Japan, and was the 129th, and last, Japanese destroyer sunk in the war.

Okinawa was declared secure by Allied forces on June 21, 1945, after an intense and costly battle. Japan surrendered unconditionally in August 1945, after being bombed twice with nuclear weapons by the U.S. The apparent willingness of Japan to sacrifice so many of their people using suicidal tactics such as Operation Ten-Go and in the Battle of Okinawa reportedly was a factor in the Allied decision to employ nuclear weapons against Japan.

The story of Operation Ten-Go is revered to some degree in modern Japan as evidenced by appearances of the story in popular Japanese culture which usually portray the event as a brave, selfless, but futile, symbolic effort by the participating Japanese sailors to defend their homeland . One of the reasons the event may have such significance in Japanese culture is that the word Yamato was often used as a poetic name for Japan itself. Thus, the end of battleship Yamato could serve as a metaphor for the end of the Japanese empire.

References

Books

• Feifer, George (2001). "Operation Heaven Number One". The Battle of Okinawa: The Blood and the Bomb. The Lyons Press. ISBN 1585742155.
• Hara, Tameichi (1961). "The Last Sortie". Japanese Destroyer Captain. New York & Toronto: Ballantine Books. ISBN 0-345-27894-1. — First-hand account of the battle by the captain of the Japanese cruiser Yahagi.
• Skulski, Janusz (1989). The Battleship Yamato. Annapolis, Maryland: Naval Institute Press. ISBN 087021019X.
• Spurr, Russell (1995). A Glorious Way to Die: The Kamikaze Mission of the Battleship Yamato, April 1945. Newmarket Press. ISBN 1557042489.
• Yoshida, Mitsuru (1999). Requiem for Battleship Yamato. Annapolis, Maryland: Naval Institute Press. ISBN 1557505446. {{cite book}}: Unknown parameter |coauthors= ignored (|author= suggested) (help) — A first-hand account of the battle by a Yamato's only surviving bridge officer, Mitsuru Yoshida.

External links

• "navweaps.com: Order of Battle". Retrieved 2006-04-22.
• "CombinedFleet.com: Chronological history of Yamato and actions during Ten-Go". Retrieved 2006-05-13.
• "NOVA documentary: Sinking the Supership". Retrieved 2006-04-23. — Official site of the NOVA documentary with additional information on the subject.

Audio/visual media

• NOVA, Sinking the Supership (Video documentary). Boston. 2005. {{cite AV media}}: Unknown parameter |crew= ignored (help); Unknown parameter |distributor= ignored (|publisher= suggested) (help) — One-hour documentary on Operation Ten-Go
• Uchu senkan Yamato (Space Battleship Yamato) (TV-series). Japan. 1974. {{cite AV media}}: Unknown parameter |crew= ignored (help); Unknown parameter |distributor= ignored (|publisher= suggested) (help) — Space Battleship Yamato is an animated series set in the future in which the wreck of the Yamato is lifted off of the ocean floor, rebuilt as a spaceship, and sent into outer space on a lone mission to defend against alien invaders who are ruthlessly bombarding the earth with huge fire bombs.
• Otoko-tachi no Yamato (A Man's Yamato) (Movie). Japan. 2005. {{cite AV media}}: Unknown parameter |director= ignored (help); Unknown parameter |distributor= ignored (|publisher= suggested) (help) — Japanese movie that dramatizes Operation Ten-Go from the perspective of Yamato's crew.