Foreign Relations of Imperial China - Sui Dynasty

Sui Dynasty

Emperor Wen of Sui ruled in northern China since 581, and conquered the Chen Dynasty in the south by 589, hence reunifying China under the Sui Dynasty (581–618). He and his successor Emperor Yang of Sui initiated several military campaigns.

Northern Vietnam was retaken by conquest, while there was a temporary occupation of the Champa Kingdom in southern Vietnam. They launched unsuccessful campaigns against the northern Korean kingdom of Goguryeo during the Three Kingdoms of Korea, depleting not only troops but ultimately much of the government's revenue.

The Grand Canal of China was completed during the Sui Dynasty, enhancing indigenous trade between northern and southern China by canal and river traffic.

One of the diplomatic highlights of this short-lived dynastic period was Prince Shōtoku's Japanese embassy to China led by Ono no Imoko in 607 AD.

Prince Shōtoku made his queen Suiko call herself Empress, and claimed an equal footing with the Chinese Emperor who regarded himself as the only Emperor in the world at that time. Thus Shōtoku broke with Chinese principle that a non-Chinese sovereign was only allowed to call himself king but not emperor.

Emperor Yang of Sui thought of this Japanese behavior as 'insolent', because it opposed his ethnocentrism of China world view, but finally, he had to accept it and send an embassy to Japan to answer a salute in the next year as he had to avoid conflict with Japan to prepare the conquest of Goguryeo .

After that the Japanese sovereign's messages to China began with the words "I, the Emperor of the land of the Rising Sun, salute you, the Emperor of the land of the sunset." (日出處天子致書日沒處天子無恙云云)