Pedzisa mutsara unotevera: Mambo Monivong paakafa musi wa23 April 1941, Gavhuna Mukuru weFrench Indochina, Jean Decoux, akasarudza Sihanouk kuti amutsive. Kusarudzwa kwaSihanouk samambo kwakarongwa zuva rakatevera neCambodian Crown Council, uye kupfekedzwa kwake korona kwakaitika musi wa 3 Chivabvu 1941. Mukati
Muchiuto cheJapan muCambodia, akapedza nguva yake yakawanda achitamba mitambo, achitora mafirimu, uye dzimwe nguva achienda kumaruwa. Muna March 1945 mauto eJapan, ayo akanga apinda muCambodia kubva muna August 1941, akaparadza hurumende yeFrench yekoloni. Vachimanikidzwa nevaJapan, Sihanouk akazivisa kuzvimiririra kweCambodia uye akava mutungamiriri wehurumende uku achishandawo samambo.