The Japanese invasion force consisting of 400 transports bearing 18,700 men under the command of Konishi Yukinaga departed from Tsushima Island on 13 April (Gregorian: 23 May) and arrived at Busan harbor without any incident, and the Japanese commenced landing operations from 04:00 am the following morning.
The commanders of the Japanese forces were Konishi, Sō Yoshitoshi, Matsura Shigenobu, Arima Harunobu, Ōmura Yoshiaki and Gotō Mototsugu, all of whom (with the exception of Matsura) were Kirishitans, as were many of their men. While Sō Yoshitoshi attacked Busan, Konishi led a smaller force against the fort of Dadaejin, located a few kilometres to the southwest of Busan at the mouth of the Nantong River.
Konishi Yukinaga’s first attack was repelled by Yun Heungsin. The second attack came at night when Japanese forces filled the moat with rocks and lumber under cover of gunfire before scaling the walls using bamboo ladders. The entire garrison was massacred.
Aftermath and Legacy
The following day, Konishi and Sō recombined their forces, and then advanced towards the fortress of Dongnae located ten kilometres northeast on the main road to Seoul.