The Righteous Armies were Korean irregular armies that emerged to fight against Japanese invasions and occupations from 1592 to 1598, in 1895, in 1905, in 1907, and in 1908. The first "Righteous armies" were raised from peasants, scholars, Confucian government officials, and Buddhist warrior-monks who were called to protect the fleeing King of Joseon as the Japanese armies of Hideyoshi Toyotomi overwhelmed Korea from 1592 to 1598, and they succeeded in frustrating Japan's supply lines and ultimately forcing Japan to retreat from Korea.
In 1895, the "Righteous armies" returned as revolutionary nationalists who, inspired by the Donghak Peasant Revolution, sought to expel the Imperial Japanese Army from Korean soil and protect Joseon's independence.
The largest of these armies, the "13-Province Alliance Righteous Army" of 1908, was crushed with a loss of 17,000 killed and 33,000 wounded, and the survivors fled to Manchuria or Russia to continue the fight against the Japanese as part of the Korean independence movement which emerged following Japan's 1910 annexation of Korea. These resistance members would go on to form the Korean Independence Army.