Hong-wu: Year 8, Month 6, Day 6
4 Jul 1375
The Grand Master for Thorough Counsel Ruan Ruo-jin, who had been sent by Chen Tuan of Annam, came to enquire of the Court the required frequency of tribute. The Emperor ordered the assembled ministers to deliberate and they jointly advised: "In ancient times, the various marquis sent a minor embassy to the Son of Heaven every year and a major embassy once every three years. However, the fan states and distant countries only needed to come to Court once every reign (世見而已)." Thus, the Secretariat officials were ordered to issue instructions to the countries of Annam, Korea and Champa, advising them that in future they needed to come to Court to offer tribute only once every three years and that it was also permissible to come just once every reign (世見可也).
Zhong-yang Yan-jiu yuan Ming Shi-lu, volume 4, page 1696/97