[2] In October 1952, it was expanded to 110,000 men and renamed as the National Safety Force (保安隊, Hoantai).

On the outbreak of the Korean War, many units of the United States Armed Forces stationed in Japan were transferred to South Korea for combat, and Japan was perceived as lacking defenses.

[3][4][2] Encouraged by the Supreme Commander for the Allied Powers (GHQ), the Japanese government in 1950 authorized the establishment of NPR, consisting of 75,000 men equipped with light infantry weapons.

[5][4] Personnel affairs of the NPR was taken charge of by GHQ's Government Section (GS) under Brigadier General Courtney Whitney[6] while the efforts to establish and train the force was made by Civil Affairs Section Annex (CASA) under Major General Whitfield P.

[10] In October 1952, the NPR was expanded to 110,000 men and renamed as the National Safety Force (NSF).