Japan’s Kyushu National Museum recently announced the discovery of Vietnam’s oldest letter sent to the Japanese government, which confirms the 400-year-old diplomatic ties between the two countries.

According to Tong Quoc Hung, deputy head of Hoi An City’s Culture and Information Department, the letter, written in 1591 under the Le The Tong reign, focused on the two countries’ diplomatic ties back then.

“This can be considered the first diplomatic document between Vietnam and Japan, though it has never been mentioned in Japanese historical records,” he said.

Reio Fujita, from the Kyushu National Museum, Japan’s fourth-largest national museum, which is located in Dazaifu in Fukuoka Prefecture, said they had bought the item from a used book store.

The letter sender was likely a high-ranking member of the Nguyen Lord’s court, during the so-called “Trinh – Nguyen war”, in which the Trinh Lord and Le King, who played a nominal role in the north, vied for power with the Nguyen Lord in the south. It is also believed that the sender was in charge of what is now the central province of Quang Nam, Fujita added.

“The letter, which indicated Vietnam’s strong resolve to do business and foster diplomatic ties with Japan, is a monumental historical record indeed,” he stressed.