Many guards groups and guerilla groups made up of young avengers were organized by members of the Children's Union in the enemy-occupied areas during the strategic temporary retreat in wartime.

The number of those groups reached nearly 60 units in October and November 1950. Among them were Yangyang children's guards, Kuksa children's operative squad, Moranbong children's guards, Anju Coal Mine children's guards, Kilju children's guards, etc. active in Pyongyang City, North and South Hwanghae, North and South Phyongan and North and South Hamgyong provinces.

They scattered leaflets with letters "Long Live General Kim Il Sung!", "Long Live the Workers' Party of Korea!" and "The People's Army Will Soon Re-advance" in the enemy-occupied areas and guided servicepersons and people on the way of retreat.

They even destroyed railways, bridges and vehicles, cut off communication lines and ruined or burned munitions, thus causing a great confusion in the enemy's maneuver, operation of military trains and communications.

In particular, the children's self-defense unit named after Hero Jo Ok Hui had only 30 members but killed or captured nearly 200 enemies during the war.

Many members of those children's groups were honored with state recommendations for their great feats performed for the victory in the war.