He, in his reminiscences "With the Century", described the meeting of Juche 20 (1931) as the start of the anti-Japanese armed struggle and a historic meeting that brought about a fresh turn in the anti-Japanese national liberation movement and communist movement in Korea.

After launching an invasion of Manchuria in the beginning of the 1930s with the Manchurian incident as an occasion, the Japanese imperialists intensified the suppression of the Korean people.

The Korean people's anti-Japanese struggle upsurged rapidly and eventually led to violence.

The President, basing himself on a scientific analysis of the prevailing situation, convened a meeting of party and young communist league cadres in Mingyuegou, Yanji County.

At the meeting he advanced a policy of launching an armed struggle based on guerrilla warfare.

He explained the difference between a regular army and a guerrilla army and said that in order to defeat the Japanese aggression forces, it was necessary to conduct such military, political and economic activities as adroit combined operations of small and large units, surprise attack, ambush, political work, political underground activities and production. He also said a guerrilla army capable of undertaking a war through repeated dispersal and gathering at will should be formed to this end.

His idea on the guerrilla warfare was a just one for dealing a heavy political and military blow to the enemy, with the guerrilla forces preserved, and defeating the enemy, superior in number and arms, with less forces.

The meeting discussed tasks and ways for the guerrilla warfare.

In 1932 a revolutionary armed unit was founded to put the Korean revolution on a higher level.