- Japanese/Chinese: 蔡 璟 (Sai Kei / Cài Jǐng)
Sai Kei was a Ryukyuan scholar-bureaucrat who led a mission to China in 1471 to formally request investiture for his king. Sai Kei (in)famously was caught by Ming Dynasty authorities and arrested for wearing a dragon robe; such iconography was strictly restricted to only members of the Imperial family, or officials of particular rank. Sai Kei protested that his kingdom had received the robe from the Ming in 1428, but Ming authorities determined that their records showed no such robes included among the gifts bestowed upon the kingdom in that year.
- Tomiyama Kazuyuki, Ryûkyû ôkoku no gaikô to ôken, Yoshikawa kôbunkan (2004), 49.