A recently opened exhibition in Dalian, Liaoning province, offers important evidence that the Ryukyu Islands, located to the northeast of China's Taiwan region, was a tributary state of China during the Ming and Qing dynasties (1368-1911), and that Japan had a record of aggression against the archipelago.

A replica of an edict from the Ming Dynasty (1368-1644) to the King of Ryukyu is on display at the exhibition, which is ongoing in Dalian's Lushun Museum, with the original preserved in the museum's archives.

The imperial document dates back to 1629, the second year of Emperor Chongzhen's reign, and it formally confirms Shang Feng's succession to the Ryukyu throne after the death of Ryukyu's King Shang Ning.

The edict praises the late Ryukyu king's loyalty and service, and urges the new ruler to govern with caution, safeguard the realm and maintain Ryukyu's duties as a tributary state. It concludes with a detailed list of imperial gifts for Ryukyu and authorizes Ming envoys to confer Emperor Chongzhen's investiture.