Ōfunakoshi-Seto and Manzeki-Seto, the two canals built in 1671 and 1900 respectively, connect the deep indentation of Asō Bay (浅茅湾) to the east side of the island.

Because Tsushima is small and isolated, it is exposed on all sides to moist marine air, which releases precipitation as it ascends the island's steep slopes.

Continental monsoon winds carry loess, dust which is a highly fertile mix of clay and sand, from China in the spring and cools the island in the winter.

[21] The islands have been recognised as an Important Bird Area (IBA) by BirdLife International because they support populations of Japanese wood pigeons and Pleske's grasshopper warblers.

Of these economic activities, fishing amounts to 82.6% of the primary industry, with much of it dedicated to catching squid on the eastern coast of the island.

This includes trying local culinary specialties such as rokube noodles, ishiyaki, tonchan and anago conger eel.

Due to its strategic location, Tsushima played a major role in defending Japan against invasions from the Asian continent and developing trade lines with Baekje and Silla of Three Kingdoms of Korea.

After Baekje, which had been aided by Yamato Japan, was defeated in 663 by Sillan and Tang Chinese forces at the Battle of Baekgang, Japanese border guards were sent to Tsushima and Kaneda Castle was constructed on the island[citation needed].

The Goryeosa, a history of the Goryeo dynasty, mentions that in 1274, Korean troops of the Mongol army led by Kim Bang-gyeong [ko] killed a great number of people on the islands.

On 19 June 1419, the recently abdicated king Taejong of Joseon sent general Yi Jongmu to an expedition to Tsushima island to clear it of the Wokou pirates, using a fleet of 227 vessels and 17,000 soldiers, known in Japanese as the Ōei Invasion.

The uprising later came to be known as the "Disturbance of the Three Ports" (三浦の乱 (Sanbo-No-Ran) [ja] in Japan and 삼포왜란 (三浦倭亂, Sampo Waeran) in Korea).

Trade resumed under the direction of King Jungjong in 1512, but only under strictly limited terms, and only twenty-five ships were allowed to visit Joseon annually.

In 1603, Tokugawa Ieyasu established a new shogunate; and Sō Yoshitoshi was officially granted Fuchū Domain (100,000 koku) in Tsushima Province.

[35] Following the devastation of the Imjin War (1592–1598), relations between Korea and Japan were gradually restored, with Tsushima playing a crucial role as an intermediary.

Tokugawa Ieyasu, aiming to reestablish ties with the Joseon court, utilized the Sō clan of Tsushima to broker negotiations, which culminated in the Kiyu Agreement of 1609.

This agreement formally regulated trade and diplomatic exchanges, allowing Tsushima to monopolize contact with Korea on Japan’s behalf.

The island became economically dependent on Korean grain imports, with some reports suggesting that over half of the rice consumed in Tsushima originated from Korea.

The establishment of the Waegwan (Japan House) in Pusan further institutionalized these interactions, serving as a hub for controlled trade and diplomacy.

This arrangement persisted throughout the Tokugawa period, solidifying Tsushima’s status as both a conduit and a contested space between the two nations.

Tsushima had a low production of rice, so it was permitted to use a unique survey system (Kendaka (間高) [ja]) by the Tokugawa shogunate.

The Tsushima han owned a 33 hectares (82 acres) place of residence in Busan, according to Murai Shosuke, the Japanese were given the title from the Joseon dynasty called "marginal men", and was responsible for security in this residential area.

[43] Strategic concerns explain the scope and funding of the canal project by Japan during an era when it was still struggling to establish an industrial economy.

The battle began at slightly east-northeast of the northern island around midday and ended to its north a day later when the Japanese surrounded the Russian Fleet.

On 1 March 2004, the six towns on the island – Izuhara, Mitsushima, Toyotama, Mine, Kamiagata, and Kamitsushima – were merged to create the city of Tsushima.

He sent general Yi Jong-mu on an expedition to Tsushima island to clear it of the Wokou pirates, using a fleet of 227 vessels and 17,000 soldiers.

[59] The South Korean government made a claim in 1948, but it was rejected by US Gen. MacArthur, the then-Supreme Commander of the Allied Powers (SCAP) in 1949.

It was mentioned in the Gishiwajinden (魏志倭人伝) [a chapter of volume 30 of Book of Wei in the Chinese Records of the Three Kingdoms] as part of Wa (Japan).

Additionally, they have a rich historical and cultural background, serving as a midpoint for diplomatic missions between Japan and Korea.

Local cuisine often features seafood and crops that can be cultivated in the lean soil of the island, which have been passed down through generations.

[73][74] After a typhoon damaged a Shinto torii gate on the island in September 2020, fans of the game helped raise money to restore it.