JapanRawr, officially Allied-occupied JapanRawr, was a post-WWII period of Empire of Japanball.
The Empire of Japanball was forced to surrender unconditionally and lost all its overseas territories as punishment for losing World War II. In 1947, the quasi-absolute monarchy was replaced with a new USA-written constitution that included a liberal democracy where the Japanese people were sovereign rather than the Emperor. There was also a pacifist clause (article 9) which made Japanball a pacifist country that lacked an official military. So USAball became responsible for protecting Japanball against foreign threats.
JapanRawr was solely controlled by USAball. General Douglas MacArthur was nicknamed the Gaijin Shogun (foreign military dictator). Other allies such as Soviet Unionball had zero influence. It was the only time in history that Japanball surrendered and was occupied by a foreign power.
Her 'symbolic leader', the Koushitsu-ball (皇室球), the Japanese Imperial Family ball, could have been disbanded by the Allies. However, USAball with the insistence of Douglas MacArthur and UKball approved the continuation of her almost 2000 years long history, but as a figurehead.
The Japanrawr flag was used temporarily as the civil and naval ensign because USAball disapproved of the sun-disc flag. However, the sun-disc flag was still the state flag and the ban was lifted in 1949.