Battle of Kōan

The Battle of Kōan (弘安の役, Kōan no eki), also known as the Second Battle of Hakata Bay, was the second attempt by the Mongol-led Yuan dynasty of China to invade Japan after their failed attempt seven years earlier at the Battle of Bun'ei. In the summer of 1281, the Yuan invaded with two large armies. The Japanese defenders were aided by a major storm which sank a sizeable portion of the Yuan fleets. The invaders who reached the shore were repulsed shortly after landing. The Japanese called the opportune storm kamikaze (lit. 'divine wind'), a name later used in the Second World War for pilots who carried out aerial suicide attacks.

Battle of Kōan
Part of the Mongol invasions of Japan
Japanese attack ships. Mōko Shūrai Ekotoba (蒙古襲来絵詞), circa 1293.
Date June 8 – August 22, 1281 Location Hakata Bay, near present-day Fukuoka, Kyūshū Result Japanese victory Invasion repulsed The Eastern route fleet destroyed and retreat of the Southern fleet
Belligerents
Kamakura Japan	Yuan dynasty Goryeo
Commanders and leaders
Hōjō Sanemasa [ja] Shōni Tsunesuke [ja] Ōtomo Yoriyasu [ja] Adachi Morimune [ja] Kōno Michiari [ja] Kikuchi Takefusa Takezaki Suenaga Shimazu Nagahisa	Atagai [zh] Fan Wenhu [zh] Hong Dagu Ala Temür [zh] † Li T'ing Kim Bang-gyeong
Strength
~40,000–60,000	~142,000 men 4,400 ships
Casualties and losses
Unknown	120,000+ ~20,000–30,000 South Chinese kept as Slaves (soon released)

Background

After the failed first invasion by the Yuan navy, the Japanese made many defense preparations, constructing numerous fortifications along the coast. Armies were kept in a state of readiness to repel a further attack.

In early 1280 Kublai Khan planned another invasion of Japan and ordered his shipbuilders to rebuild the whole fleet within a year. In the short time available many of the ships were poorly made; many were flat-bottomed river boats requisitioned by the Emperor.

Battle

By June 1281, 900 Yuan ships were gathered in Korea; the force was called the Eastern Route Army. They were crewed by 17,000 sailors, and transported 10,000 Korean soldiers and 15,000 Mongols and Chinese. The Southern Route Army, meanwhile, was assembled just south of the Yangtze River, in China. It is said to have consisted of 100,000 men on 3,500 ships. As before, Iki and Tsushima islands fell quickly to the much larger Yuan forces.

The Eastern Route Army arrived at Hakata Bay on June 23, and decided to proceed with the invasion without waiting for the larger Southern force which had still not left China. They were a short distance to the north and east of where their force had landed in 1274, and were in fact beyond the walls and defenses constructed by the Japanese. The samurai responded quickly, assaulting the invaders with waves of defenders, denying them the beachhead.

At night small boats carried small bands of samurai into the Yuan fleet in the bay. Under cover of darkness they boarded enemy ships, killed as many as they could, and withdrew before dawn. This harassing tactic led the Yuan forces to retreat to Tsushima, where they would wait for the Southern Route Army. However, over the course of the next several weeks, 3,000 men were killed in close quarters combat in the hot weather. Yuan forces never gained a beachhead.

The first of the Southern force ships arrived on July 16, and by August 12 the two fleets were ready to attack Japan. On August 15 a major tempest struck the Tsushima Straits, lasting two full days and destroying most of the Yuan fleet. Contemporary Japanese accounts indicate that over 4,000 ships were destroyed in the storm; 80% of the Yuan soldiers either drowned or were killed by samurai on the beaches. The loss of ships was so great that "a person could walk across from one point of land to another on a mass of wreckage".^[1]

Main battles of the Kōan Campaign

Battle of Tsushima Island

On June 8, the Yuan Army landed on Tsushima island. According to the History of Yuan, the Japanese commander Shōni Suketoki and Ryūzōji Suetoki led forces against the invasion force. The expeditionary forces discharged their firearms, and the Japanese were routed, with Suketoki killed in the process. More than 300 islanders were killed. ^[2]

Battle of Shika Island

On June 23, unable to land in Hataka, the Yuan fleet occupied the islands of Shika and Noko from which it had planned to launch raids against Hakata. By June 24, Mongolian forces had control of most of the island, but on the morning of June 25, the Japanese army divided their force into two and attacked along Umi no Nakamichi.^[3] Several clashes followed resulting in 300 casualties for the Japanese army.^[4]

Japanese soldiers in Shika Island

On June 26, the japanese forces launched a surprise night attack on Zhang Cheng, his unit held their position on the ships and fought through the night. By dawn, the japanese ships retreated.^[5] The following days, the japanese forces again assembled a large army for battle but they were routed, many were killed or wounded.^[5]

Battle of Iki Island

On July 16, a Japanese army of approximately 10,000, led by the Matsura clan, Ryūzōji clan and Takagi clan began an all-out attack on Iki Island.^[6] On July 18, Ryūzōji Iekiyo (龍造寺家清) landed on Setoura beach and defeated the Mongolian army. As a result, the Mongolian army abandoned Iki Island and withdrew to Hirado Island.^[7]

Battle of Mikuriya

On 15 August, a great typhoon, known in Japanese as kamikaze, struck the Yuan fleet at anchor from the west and devastated it. Sensing the oncoming typhoon, Korean and south Chinese mariners retreated and unsuccessfully docked in Imari Bay, where they were destroyed by the storm. On August 20, Takezaki Suenaga attacked the stranded ships.^[8] After this battle, most of the commanders of the Mongolian army escaped to their own country.^[9]

Takezaki Suenaga attacking Yuan ships in Mikuriya

Battle of Taka Island

On August 22, 100,000 soldiers of the Yuan fleet remained marooned on Taka island without commanders.^{[9][10][11][12]} Upon realizing the situation, the Japanese army launched an assault. Togō Korechika, Togō Koretō, Fujiwara no Sukekado, and Shimazu Nagahisa led the charge, successfully defeating the remaining Yuan forces. They captured between 20,000 and 30,000 prisoners during the battle, killing the rest.

Fierce battle in Taka Island

Aftermath

Kublai Khan began to gather forces to prepare for a third invasion attempt, but was soon distracted by events in Southeast and Central Asia,^{[citation needed]} and no third attempt was ever made.

See also

• Battle of Bun'ei - the first invasion attempt by Kublai Khan, in 1274.
• Mongol invasions of Japan