Japan’s historic relationship with the Korean Peninsula has often been complicated by mutual misunderstanding and distrust, if not outright hostility. But on Tsushima, a Japanese island off the coast of the peninsula, efforts are being made to celebrate long-ago diplomatic missions with Korea that took place for the purposes of peaceful coexistence and trade during Japan’s period of isolation in the 17th through 19th centuries.

Last October, UNESCO’s Memory of the World heritage program agreed to register 333 diplomatic documents, travel records and records of cultural exchanges of a dozen missions by Korean envoys to Japan between 1607 and 1811. Of these, 209 items are held in Japan and 124 in South Korea. The registration effort was the result of years of joint cooperation by both countries.

“The missions benefited not only the two countries, but also East Asia as a whole by stabilizing the political situation and maintaining trading channels,” Japan and South Korea said in the 2016 application to UNESCO.

Each journey to Japan involved a round trip of 4,500 kilometers between Hanyang (now Seoul), and Edo (Tokyo). Along the way, the envoys, numbering in the hundreds, stopped in or passed through towns in modern Fukuoka, Yamaguchi, Hiroshima, Okayama and Hyogo prefectures before arriving in Osaka and Kyoto, and then heading to Tokyo.

“Tsushima had undertaken trade and diplomacy with Korea, and it was the first place in Japan the Korean envoys came to before traveling across western Honshu to Edo, ” said Shigeki Kojima, an official with the city of Tsushima’s cultural exchange section.

The story of the envoys to Japan begins with a crime, in this case counterfeiting, on Tsushima. A few years after the unsuccessful invasion of Korea by Japanese feudal lord Toyotomi Hideyoshi, in which he’d ordered the lord of the Tsushima domain to prepare the way for invasion, the king of Korea’s Joseon dynasty sent official letters to the Tokugawa shogun.

The lord of Tsushima, who understood how testy Edo political types were about foreign trade, decided to make counterfeits of those first letters for reasons lost to history but, no doubt, in the hope that his edits would lead to better trade relations between Japan and Korea. “Despite the counterfeiting, these fake letters were received by the shogun and actually functioned as diplomatic documents,” the official UNESCO application reads.

The registered collection includes diplomatic notes, lists of gifts given to the shogun, and even poems composed in the various stops along the way (the Korean retinue actually included a secretary who was responsible for exchanges of written communication, including poems between the envoys and their Japanese hosts). This official, who traveled to Japan in 1719-1720, also kept a diary of his trip, making notes on the country’s topology, social systems, daily life, and scholarly activities.

“Communication was not difficult because both parties were familiar with Chinese characters and sentence structures. Conversations were held by writing classical Chinese sentences, which were understood well by both parties. Even Chinese-style poems were composed by both parties in turn,” the joint application to UNESCO read.

And, of course, there were paintings. One of the items registered is a painting of the 1711 mission to Japan. Tawara Kizaemon, a Tsushima-based painter, and Edo-based artists worked for nearly five months, producing 14 volumes of paintings of that year’s mission.

In order to make some of the items located on Tsushima more publicly accessible, the city is now constructing a new museum to house the records and other documents. It is expected to open in 2020. But officials hope it will be more than just a library.

“In addition to records of the envoys here in Tsushima, the new museum will include models of the ships they used. We hope it will attract visitors from all over the world,” Tsushima Mayor Naoki Hitakatsu told the city assembly in December.

Given that Tsushima has always been an international crossroads of trade, the city is working to ensure modern visitors who have trouble reading ancient texts or fully understanding Edo Period relations with Korea can still find unique gift items for friends and family.