Katō Kiyomasa, leading the Second Division of more than 20,000 men, crossed the peninsula to Anbyon County with a ten-day march, and swept north along the eastern coast. Among the castles captured was Hamhung, the provincial capital of Hamgyong Province. There a part of the Second Division was assigned to defense and civil administration.

The rest of the division, 10,000 men, continued north, and fought a battle on August 23 against the southern and northern Hamgyong armies under the command of Yi Yong at Songjin. A Korean cavalry division took advantage of the open field at Songjin, and pushed the Japanese forces into a grain storehouse. There the Japanese barricaded themselves with bales of rice, and successfully repelled a charge from the Korean forces with their arquebuses. While the Koreans planned to renew the battle in the morning, Katō Kiyomasa ambushed them at night; the Second Division completely surrounded the Korean forces with the exception of an opening leading to a swamp. Those that fled were trapped and slaughtered in the swamp.

Koreans who fled gave alarm to the other garrisons, allowing the Japanese troops to easily capture Kilju County, Myongchon County, and Kyongsong County. The Second Division then turned inland through Puryong County toward Hoeryong, where two Korean princes had taken refuge. On August 30, 1592, the Second Division entered into Hoeryong where Katō Kiyomasa received the Korean princes and the provincial governor Yu Yong-rip, these having already been captured by the local inhabitants. Shortly afterward, a Korean warrior band handed over the head of an anonymous Korean general, plus General Han Kuk-ham, tied up in ropes.