was a Sō clan

So clan

The Sō were a Japanese clan claiming descent from Taira Tomomori. The clan governed and held Tsushima Island from the 13th-century through the late 19th-century, from the Kamakura period until the end of the Edo period and the Meiji restoration....

 daimyō (feudal lord) of the island domain of Tsushima

Tsushima Fuchu domain

The Tsushima Fuchū domain , also called the Tsushima domain, was a domain of Japan during the Edo period that controlled Tsushima Province and a small portion of Hizen Province. It was ruled by the Sō clan...

 at the end of Japan's Sengoku period

Sengoku period

The or Warring States period in Japanese history was a time of social upheaval, political intrigue, and nearly constant military conflict that lasted roughly from the middle of the 15th century to the beginning of the 17th century. The name "Sengoku" was adopted by Japanese historians in reference...

, and into the Edo period

Edo period

The , or , is a division of Japanese history which was ruled by the shoguns of the Tokugawa family, running from 1603 to 1868. The political entity of this period was the Tokugawa shogunate....

. His name is sometimes read as Yoshitomo. Under the influence of Konishi Yukinaga

Konishi Yukinaga

Konishi Yukinaga was a Kirishitan daimyō under Toyotomi Hideyoshi. He was the son of a wealthy Sakai merchant, Konishi Ryūsa...

 he was baptized and accepted the name "Dario". He took part in Toyotomi Hideyoshi

Toyotomi Hideyoshi

was a daimyo warrior, general and politician of the Sengoku period. He unified the political factions of Japan. He succeeded his former liege lord, Oda Nobunaga, and brought an end to the Sengoku period. The period of his rule is often called the Momoyama period, named after Hideyoshi's castle...

's invasions of Korea in the 1590s, and led a force in the Siege of Busan

Siege of Busan

The Siege of Busan was a battle fought at Busan on April 13th-14th, 1592, between Japanese and Korean forces. Along with Tadaejin, Busan was the site of the first battle in the Imjin War. This battle marked the beginning of a long war on the Korean peninsula....

.

The Sō clan did not participate in the Battle of Sekigahara

Battle of Sekigahara

The , popularly known as the , was a decisive battle on October 21, 1600 which cleared the path to the Shogunate for Tokugawa Ieyasu...

 in 1600; however, the tozama

Tozama

A ' was a daimyo who was considered an outsider by the rulers of Japan. The term came into use in the Kamakura period and continued until the end of the Edo period.-Edo period:...

Sō clan were allowed to continue to rule Tsushima.

Yoshitoshi was the fifth son of Sō Masamori; his wife, who took the baptismal name Maria, was the daughter of Konishi Yukinaga. Yoshitoshi became the head of the family in 1580, after his adoptive father, Sō Yoshishige, was defeated, and Tsushima conquered, in a prelude to Toyotomi Hideyoshi's Kyūshū Campaign

Kyushu Campaign

The Kyūshū Campaign of 1586-1587 was part of the campaigns of Toyotomi Hideyoshi who sought to dominate Japan at the end of the Sengoku period...

. Yoshitoshi thus entered Hideyoshi's service, and began organizing negotiations with Korea, as Hideyoshi's representative. The Joseon

Joseon Dynasty

Joseon , was a Korean state founded by Taejo Yi Seong-gye that lasted for approximately five centuries. It was founded in the aftermath of the overthrow of the Goryeo at what is today the city of Kaesong. Early on, Korea was retitled and the capital was relocated to modern-day Seoul...

 king refused to allow Japanese troops to pass peacefully through Korea in an attempt to conquer Ming Dynasty

Ming Dynasty

The Ming Dynasty, also Empire of the Great Ming, was the ruling dynasty of China from 1368 to 1644, following the collapse of the Mongol-led Yuan Dynasty. The Ming, "one of the greatest eras of orderly government and social stability in human history", was the last dynasty in China ruled by ethnic...

 China

China

Chinese civilization may refer to:* China for more general discussion of the country.* Chinese culture* Greater China, the transnational community of ethnic Chinese.* History of China* Sinosphere, the area historically affected by Chinese culture...

, and the negotiations ultimately proved entirely fruitless, leading to Hideyoshi's decision to invade Korea militarily.

In 1587, Toyotomi Hideyoshi

Toyotomi Hideyoshi

was a daimyo warrior, general and politician of the Sengoku period. He unified the political factions of Japan. He succeeded his former liege lord, Oda Nobunaga, and brought an end to the Sengoku period. The period of his rule is often called the Momoyama period, named after Hideyoshi's castle...

 confirmed the Sō clan possession of Tsushima.

Yoshitoshi played a crucial role in Hideyoshi's invasions of Korea, as a result of Tsushima's strategic location between Japan and Korea, and his knowledge of, and experience with, Korea. He thus led the first major land assault of the war, the siege of Pusan, on 13 April 1592, while Konishi Yukinaga attacked the Korean naval fortress. He continued his command through a number of the ensuing engagements.

After Sekigahara

Shortly after news of the Toyotomi

Toyotomi clan

Originating in Owari Province, the served as retainers to the Oda clan throughout 16th-century Japan's Sengoku period. -Unity and Conflict:The most influential figure within the Toyotomi was Toyotomi Hideyoshi, one of the three "unifiers of Japan." Oda Nobunaga was another primary unifier and the...

 defeat at the Battle of Sekigahara

Battle of Sekigahara

The , popularly known as the , was a decisive battle on October 21, 1600 which cleared the path to the Shogunate for Tokugawa Ieyasu...

 was received by the Joseon Court, a process of re-establishing diplomatic relations was initiated by Ieyasu Tokugawa in 1600. As an initial gesture and as an earnest of future progress, some Joseon prisoners were released at Tsushima Island

Tsushima Island

Tsushima Island is an island of the Japanese Archipelago situated in the middle of the Tsushima Strait at 34°25'N and 129°20'E. The main island of Tsushima was once a single island, but the island was divided into two in 1671 by the Ōfunakosiseto canal and into three in 1900 by the Manzekiseto canal...

. In response, a small group of messengers under the leadership of Yu jeong

Samyeongdang

Samyeongdang , also known by his Buddhist name, Yujeong , was a Korean Buddhist monk during the Joseon Dynasty. He is sometimes identified by his pen name, Song-un. He was born to a family of the Im clan in Miryang, Gyeongsang province...

 were sent to Kyoto to investigate further. With the assistance of Sō Yoshitomo, an audience with Ieyasu was arranged at Fushimi Castle

Fushimi Castle

', also known as Momoyama Castle or Fushimi-Momoyama Castle, is a castle in Kyoto's Fushimi Ward. The current structure is a 1964 replica of the original built by Toyotomi Hideyoshi.-History:...

 in Kyoto

Kyoto

is a city in the central part of the island of Honshū, Japan. It has a population close to 1.5 million. Formerly the imperial capital of Japan, it is now the capital of Kyoto Prefecture, as well as a major part of the Osaka-Kobe-Kyoto metropolitan area.-History:...

.

In 1603, Tokugawa Ieyasu

Tokugawa Ieyasu

 was the founder and first shogun of the Tokugawa shogunate of Japan , which ruled from the Battle of Sekigahara  in 1600 until the Meiji Restoration in 1868. Ieyasu seized power in 1600, received appointment as shogun in 1603, abdicated from office in 1605, but...

 established a new shogunate; and Sō Yoshitoshi was officially granted Fuchu Domain (100,000 koku) in Tsushima Province

Tsushima Province

was an old province of Japan on Tsushima Island which occupied the area corresponding to modern-day Tsushima, Nagasaki. It was sometimes called .-Political History:...

.

In 1604, Yu jeong confirmed the Joseon interest in developing further contacts; and the Tokugawa shogun reciprocated by releasing 1,390 prisoners-of-war.

Yoshitomo's descendants held this domain until the abolition of the han system. The Sō would remain the shogunate's intermediaries with the Joseon government throughout the Edo period

Edo period

The , or , is a division of Japanese history which was ruled by the shoguns of the Tokugawa family, running from 1603 to 1868. The political entity of this period was the Tokugawa shogunate....

 (1603-1868); and the clan would profit politically and economically.

As representatives and spokesmen for the Tokugawa, the Sō helped make to ensure the continuing series of major Joseon missions to Edo (Joseon tongsinsa). These benefited the Japanese as legitimizing propaganda for the bakufu (Tokugawa shogunate) and as a key element in an emerging manifestation of Japan's ideal vision of the structure of an international order with Edo as its center.

In 1884, the head of this clan line was ennobled as a "Count".