Japanese forces seized the Korean Peninsula rapidly through land battles, but lost battles at sea during the initial states of the Korea war. However, they continued to firmly hold occupied cities and withstood attacks from Korea and Ming troops. Finally, they resisted the navies of the said two countries in the later stages. Various factors impacted this shift, but the application of tactics cannot be neglected. This study analyzes the tactics employed in land and sea battles and compares Japanese tactics with Korea and Ming ones in regards to the application of fortification, attack and defense, and weaponry by Japanese forces.