During the reign of King Goi in the 3rd century, the Baekje kingdom saw a major turning point in its foreign relations, especially with Chinese-controlled commandery, such as Lelang and Daifang. When King Goi attacked Daifang located in present-day Shandong Province in eastern China, the commandery governor Gong Zun was killed. But later, the king accepted Daifang’s princess as his daughter-in-law. The marriage shows that the two enemy states reconciled and Daifang was actually under the influence of Baekje. That is to say, it is assumed that Baekje began to control the Shandong area during the period of King Goi.

In relation to its eastern rival Silla, Baekje maintained a hard-line policy in the initial stage of King Goi, but entered into friendly relations later. There are no records about war between the two kingdoms in the subsequent decades. Notably, Baekje was at peace with its longtime foe, Malgal. It is said that Malgal offered ten fine horses to King Goi in an apparent bid to form friendly relations with Baekje. This also indicates that Malgal viewed Baekje as an emerging power, which was quite strong at the time.

King Goi made remarkable achievements in domestic affairs as well. In 260, he introduced a governing system comprising six ministers and divided government posts into 16 different ranks to carry out a massive administrative reform. He also set up a military office with the purpose of weakening the power of regional clans. In addition, he adopted a new code of dress for government officials, who were supposed to wear dresses with different colors in accordance with their ranks. All these measures were aimed at concentrating royal power and establishing a centralized state. The king also enacted a law that bans public officials from receiving bribes. Those who violated the law were required to repay three times the amount of the bribe and to serve life imprisonment. This reflects that the king tried to tighten discipline among government officials.

On the economic front, the king ordered the cultivation of farmlands in the southern area to increase agricultural productivity. Clearly, Baekje had sufficient assets in its state coffers at the time. When a drought hit the country, the king opened the coffers to save the starving people and he exempt them from taxes for one year.

During his 52-year reign from 234 to 286, the king successfully arranged the state structure and laid the foundation for territory expansion. Thanks to his achievements both inside and outside the nation, Baekje was able to develop in various areas and enhance its national status.