Letter by Minister Phúc Nghĩa Hầu of Cochinchina to the King of Japan

This is the oldest known diplomatic letter exchanged between Japan and Annam (present-day Vietnam). The letter is dated the 14th year of the Guangxing era of Annam, which corresponds to 1591 C.E. The letter was written by Nguyen and his signature was affixed at the end with a wooden seal. It is addressed to King x of Japan (the name of the king is intentionally omitted.). Right above the signature seal is another seal with the Chinese character "書" (sho), which means that this document is a letter. The “King of Japan” here intended to have trading relationship with Annam from around 1590. Around the time, Toyotomi Hideyoshi was seeking tributes from Korea, Ryūkyū (present-day Okinawa), Takasago (present-day Taiwan), and Luzon (present-day Philippines). Thus, he might have made the same request to Annam. On the other hand, it is possible that Chinese merchants tried to expand their trading zone under the guise of Toyotomi Hideyoshi. Whichever may have been the truth, this letter is an important material indicating Japan-Annam relationship during the transition from the period of Wako (Chinese pirates) to the period of the Red Seal system and awaits further studies.