Invasion of Ryukyu

The invasion of Ryukyu (琉球征伐) by forces of the Japanese feudal domain of Satsuma took place in 1609, and marked the beginning of the Ryūkyū Kingdom's status as a vassal state under Satsuma. The invasion itself involved few casualties, as Ryukyu had little military strength, and its people were ordered by their king to surrender and to spare themselves any bloodshed.

Ryukyu would remain a vassal state under Satsuma, alongside its already long-established tributary relationship with China, until it was formally annexed by Japan in 1879 as Okinawa Prefecture.

Background
Satsuma's invasion of Ryukyu was the climax of a long tradition of relations between the kingdom and the Shimazu clan of Satsuma. The two regions had been engaged in trade for at least several centuries and possibly for far longer than that; in addition, Ryukyu at times had paid tribute to the Muromachi shogunate (1336–1573) of Japan as it did to China since 1372.

In the final decades of the 16th century, the Shimazu clan, along with Toyotomi Hideyoshi, who ruled Japan from 1582 to 1598, requested or demanded various types of aid or service from the kingdom on a number of occasions. King Shō Nei (r. 1587–1620) met some of these demands. Sho Nei sent a tribute ship, the Aya-Bune, to Satsuma in February or March, 1592, and agreed to provide approximately half of his allocated burden in preparation for the invasion of Korea, in 1593. However, Sho Nei also ignored many communications from Shimazu and Hideyoshi, which spurred the Shimazu, with the permission of the newly established Tokugawa shogunate (1603–1867), to invade Ryukyu in 1609, claiming it a punitive mission.

One of the chief events which spurred Satsuma to aggression occurred when Hideyoshi launched the first of two invasions of Korea. In 1591, Shimazu Yoshihisa said that "Hideyoshi ordered Ryukyu and Satsuma to contribute 15000 troops in order to invade China; however, Ryukyu is a far country and Japanese military strategy is unfamiliar to your forces. I exempt you from mobilization of the troops. In exchange, however, you must supply 10 months' rations for 7000 troops. " Sho Nei supplied only half in 1593.

Following Hideyoshi's death in 1598, and Tokugawa Ieyasu's subsequent rise to power, Shō Nei was asked by Satsuma to formally submit to the new shogunate, a request which was ignored. In 1603, some Ryukyu sailors were cast ashore on the coast of the Sendai domain. Tokugawa Ieyasu sent them back to Ryukyu. The Shimazu asked Ryukyu to thank Ieyasu again, but Ryukyu ignored the request. The Shimazu then requested to launch a punitive mission against Ryukyu. Approximately 100 ships carrying roughly 3,000 soldiers concentrated at Yamakawa harbor on March 1, 1609. Ichirai Magobee, who was one of them, would write a diary documenting the expedition. The fleet left harbor on March 4, under the command of Kabayama Hisataka and Hirata Masumune.

Invasion of Amami Ōshima
The Satsuma fleet arrived at Amami Oshima (Great Amami island) on March 7. The Oshima people did not resist, but assisted the Satsuma army. Tameten (笠利首里大屋子為転), the chief of Kasari, was subject to Kabayama, and called on the Oshima people to surrender. Shigetedaru (焼内首里大屋子茂手樽), the chief of Yakiuchi, supplied Satsuma army. On March 16, 13 ships　left for Tokunoshima in advance. Others left Oshima at 0600, March 20.

On March 10, Sho Nei was informed Satsuma's arrival at Ooshima. He sent Ibun (天龍寺以文長老), the priest of Tenryu temple, to Oshima in order to surrender. But Ibun missed contact Satsuma army. The reason was unclear.

Invasion of Tokunoshima
At March 17, 13 ships arrived at Tokunoshima. Two ships arrived at Kanaguma, and nothing happened. Eight ships arrived at Wanya. Ships were besieged all night by 1000 people. On March 18, Satsuma troops got off the ships, fired, and killed 50 people. Three ships arrived at Akitoku. They were attacked at water's edge by Akitoku people. However, troops quickly fought back and killed 20-30 people.

The Satsuma fleet arrived at Akitoku at 1600, March 20. At March 21, Kabayama left for Okierabu island with 10 ships in advance. Others left Tokunoshima at 1000, March 24, and arrived at Okierabu at sunset. They met Kabayama and his ships there, and quickly left for Ryukyu island.

Invasion of Ryukyu island
The Satsuma fleet arrived Unten harbor on the Motobu Peninsula of Ryukyu Island at 1800, March 25. At March 27, some disembarked. They found Nakujin castle deserted. They set fire in several places.

As soon as Sho-Nei heard Satsuma's arrival at Nakijin, he called Kikuin (菊隠 ) the zen master. He gave imperial order to Kikuin, "You had lived in Satsuma for several years, so you know 3 lords of Shimazu clan very much. Go and make a proposal for peace. "Kikuin and his diplomatic mission (Kian was a stuff) left Ryukyu royal capital, Shuri at 0800, March 26, arrived at Kuraha at 1200. They left Kuraha for Onna by boat. At March 27, they left Onna by boat, and arrived at Nakijin. Kikuin talked with Kabayama. Kabayama ordered peace talks at Naha.

In the early morning of March 29, the Satsuma fleet and Kikuin left Unten harbor. They arrived at Oowan at 1800. The Ryukyu mission left immediately, and arrived at Makiminato at 2200. They left their boat for Shuri there, and arrived late at Night. Kikuin reported Kabayama's order to Sho-Nei, and went down to Naha towards daylight.

At Oowan, Kabayama sent his some officers to Naha in order to fulfill his promise, while he disembarked his other men, because he heard that there was a chain at the entrance of Naha harbor. "If there is a chain, no ship can enter the harbor. "In order to prepare the worst,He prepared to attack Shuri.

At 1400, April 1, Satsuma ships entered Naha harbor. Immediately they held peace talks at Oyamise (親見世) in Naha. At that time, there was a fire in Shuri. Satsuma army invaded. Some Satsuma officers ran up to Shuri from Naha, and calmed down their own military forces. Because Syo-Nei gave Kabayama his own brother Sho-Ko (尚宏 ), and all of his 3 ministers as hostage, Kabayama ordered his men to go down to Naha. All of the Satsuma army arrived at Naha at 1600, April 1.

At April 4, Sho-Nei deserted the Shuri castle. At April 5, some officers entered the castle, and started making an inventory of treasures in the castle.

At May 17, Syo-Nei left Unten harbor for Satsuma along with roughly one hundred of his officials. At August, 1610, He met with the retired Shogun Tokugawa Ieyasu in Sunpu. He was then taken to Edo, for a formal audience with Shogun Tokugawa Hidetada at August 28. At December 24, He arrived at Kagoshima, where he was forced to formally surrender and to declare a number of oaths to the Shimazu clan. In 1611, two years after the invasion, the king returned to his castle at Shuri.

In the king's absence, Kabayama Hisataka and his deputy Honda Chikamasa governed the islands on behalf of their lord Shimazu Tadatsune. Fourteen samurai officials from Satsuma, along with 163 of their staff, examined the kingdom's political structures and economic productivity, and conducted land surveys of all the islands. Following the king's return to Shuri and the resumption of governance under the royal establishment, some Ryukyu officials went Kagoshima as hostages. Kunigami Aji Seiya(国頭按司正弥) lived in Kagoshima for 1614-1616. He served Shimazu Iehisa in battle in the 1615 siege of Osaka, but the war was over before their arrival.

Consequences
The surrender documents signed at Kagoshima in 1611 were accompanied by a series of oaths. The king and his councilors were made to swear that "the islands of Riu Kiu have from ancient times been a feudal dependency of Satsuma", and that there was a long-standing tradition of sending tribute and congratulatory missions on the succession of the Satsuma lords; though these were all falsehoods. The oaths also included stipulations that the kingdom admit its wrongdoing in ignoring and rejecting numerous requests for materials and for manpower, that the invasion was justified and deserved, and that the lord of Satsuma was merciful and kind in allowing the king and his officers to return home and to remain in power. Finally, the councilors were forced to swear their allegiance to the Shimazu over their king. Tei Dō, a royal councilor and commander of the kingdom's defense against the invasion, refused to sign the oaths and was beheaded.

The kingdom's royal governmental structures remained intact, along with its royal lineage. The Ryukyus remained nominally independent, a "foreign country" (異国, ikoku) to the Japanese, and efforts were made to obscure Satsuma's domination of Ryukyu from the Chinese Court, in order to ensure the continuation of trade and diplomacy, since China refused to conduct formal relations or trade with Japan at the time. However, though the king retained considerable powers, he was only permitted to operate within a framework of strict guidelines set down by Satsuma, and was required to pay considerable amounts in tribute to Satsuma on a regular basis.

This framework of guidelines was largely set down by a document sometimes called the Fifteen Injunctions (掟十五ヶ条, Okite jūgo-ka-jō), which accompanied the oaths signed in Kagoshima in 1611, and which detailed political and economic restrictions placed upon the kingdom. Prohibitions on foreign trade, diplomacy, and travel outside of that officially permitted by Satsuma were among the chief elements of these injunctions. Ryukyu's extensive trade relations with China, Southeast Asia, and Korea were turned to Satsuma's interests, and various laws were put into place forbidding interactions between Japanese and Ryukyuans, travel between the two island nations. Likewise, travel abroad from Ryukyu in general, and the reception of ships at Ryukyu's harbors, were heavily restricted with exceptions made only for official trade and diplomatic journeys authorized by Satsuma.

In addition, Amami Ōshima and a number of other northern islands now known as the Satsunan Islands were annexed into Satsuma Domain and removed from the kingdom's territory. These islands remain today part of Kagoshima Prefecture, not Okinawa Prefecture.