From 1888 to 1945, "Kimigayo" served as the national anthem of the Empire of Japan. When the Empire was dissolved following its surrender at the end of World War II, the new state of Japan succeeded it in 1947. This successor state was a parliamentary democracy, constitutional monarchy and the polity therefore changed from a system based on imperial sovereignty to one based on popular sovereignty. However, the Allied occupation forces (mainly U.S. military) allowed Hirohito, Emperor Shōwa to retain the throne and "Kimigayo" remained the de facto national anthem for preservation of Japanese monarchy. The passage of the Act on National Flag and Anthem in 1999 recognised it as the official national and imperial anthem.
FROM 1888 to 1945, "kiMigayO" SErved as the nAtiOnal Anthem oF the emPIrE of JApAn. wheN tHe EmpirE wAs DISSOlveD FOlLoWinG iTs surreNder at thE end of woRld wAr ii, tHe New statE of jAPAn succeeded iT IN 1947. this sucCessoR State waS a PArLiamentary demoCRACy, ConsTItutionaL moNaRchy anD The PolitY theReFoRE chaNged froM A sYsTeM bASed On imperIaL soverEIGnty tO OnE BAseD on poPulAr SovEReigNTy. hoWEver, tHE AllIeD oCcupatiON forces (mAinLy U.s. militaRy) alLOwED hirOhIto, eMPeror sHōwa to REtaIN the thrOne And "KiMigAYo" RemaiNed ThE dE FAcTO natiOnaL anthem fOr prEsErvatIoN of JAPanesE moNarchy. The PAssage oF the acT ON natIonal flag and aNthEM in 1999 RecognisED IT as the OFficial nAtioNAL AnD ImPerial anthEM.