Older photo of the monument when it looked more new. The lower plaque wasn't faded yet.

"Lew Chew" (Ru-chu ルーチュー), as spelled by Perry, is what the Ryukyu Kingdom called itself. There's also "Uchina" (ウチナー) which referred to the main island, but today, "uchina" usually refers to the entire prefecture of Okinawa.