In Japanese Invasion, as the righteous monk army was the military group to rise spontaneously in revolt, they make some military achievements as much as the Joseon forces(官軍) or the righteous army. But they was the status of monk, so there was the rigidly compartmentalized character into the righteous monk army against the righteous army. The righteous monk army had a distinct command system in the structure of it like the Dochongseob(都摠攝) to generalize the righteous monk army of 8 provinces and the Chongseob(總攝) to control over the righteous monk army of each provinces. They were granted autonomy and took their own way as the righteous army in their early period of revolt. After the Joseon forces were gradually reorganized a line of battle and recovered the faculty of battle, the righteous monk army were transfigured the paramilitary formation to be generalized from a general of the army(都元帥). The change of the character on the righteous monk army took from the change of the function on it. However there are many combative activity in their early period, they had been adjusted to their function after the. entry of auxiliary troops of Ming(明) Dynasty and the recovering of ability of accomplishing combat by Joseon forces. Sahmyoungdang specially played a central role in the action of the righteous monk army, and he took an active part after August in 1592. Sahmyoungdang practically commanded the righteous monk army for Hyujeong(休靜). Sahmyoungdang led a force of the righteous monk army into Pyoungyangsttng(平壤城) battle and Nowonpyoung(蘆原坪) battle which was a key factor on the recovery of the capital. In the Pyoungyangsung battle, the righteous monk army to be led by Sahmyoungdang achieved more brilliant war results than the Ming forces or the Joseon forces. Before the combat, they had cut off enemy's supply routes of provisions and manoeuvre routes, so they could make the preparation of Japanese forces for battle difficult. And after taking part in combat operations, they gained an advantage over an opponent to have a good grasp of ground, so they could fight in the vanguard of battle. Sahmyoungdang commanded the righteous monk army to come to the south, and watched for an opportunity to recover the capital. At last he made marked military achievements against Japanese army, which went out of a castle to seek scarce provisions, with Go eon-bag(~&1B) in the Nowonpyoung battle. In conclusion the righteous monk army played the significant role to overcome the national critical situation as the Japanese Invasion. The foundation on it could be found from the traditional ethos like the Buddhism for defense of the fatherland which planted its roots deeply in the past generation.