Two other powerful states had meanwhile emerged north of the peninsula around the time of Christ—Buyeo in the Sungari River Basin in Manchuria, and Goguryeo, Buyeo's frequent enemy to its south, near the Yalu River.

Goguryeo, which also exercises a lasting influence on Korean history, develops in confrontation with the Chinese.

Puyo is weaker and seeks alliances with China to counter Goguryeo but eventually succumbs around 312.

Goguryeo is expanding in all directions, in particular toward the Liao River in the west and toward the Taedong River in the south.

In 313 Goguryeo occupies the territory of Lelang and comes into conflict with Baekje.