1. Hiromichi Kumazawa: Sent letters to various public officials declaring he was Emperor in 1920, and continued protesting his imperial lineage thereafter while running a general store in Nagoya. In 1945, his petition to MacArthur was spotted in the messy GHQ headquarters by a reporter for Life magazine and he became internationally famous for a short time. Lost many of his supporters in 1947 when he formed a political party, at which point he made the unusual claim that the Takenouchi Documents were real and had been stolen from his household by a wandering komusō during the Meiji period. His death in 1966 went unreported in the West.
Prominent supporter, Masanori Arita: Shady right-wing character who supported Kumazawa from the 1920s and cared for him until his death. Became private secretary to fascist underworld power broker Ryoichi Sasakawa who is a well-known philanthropist in Africa. It is unknown if Arita is still alive.
Apparent relative, Terumoto Kumazawa: Claimed that Hiromichi Kumazawa was adopted and that he was the true ruler of the Kumazawa household. (There are four other Kumazawas claiming to be the true Kumazawa Emperor, whom I will not list here.)
2. Tatsukichirou Horiwaka: A mysterious person who was rumored to be the illegitimate child of the Meiji Emperor. Actual place and time of birth unknown. Advocated for Pan-Asianism during the kindai, was involved in the Treaty of San Francisco for unknown reasons, and joined the World Federalist Movement after 1945.
Pretended daughter, Princess Kaoru Nakamaru: Journalist who interviewed business leaders, authors such as Norman Mailer, and world leaders such as Saddam Hussein for PBS in the 1980s, later Illuminati researcher and founder of “Taiyo no Kai” (organization of unclear purpose). Notable Japanese 2012 theorist who has written roughly a dozen books about 2012. Despite her claims it is not generally believed that she is actually Horikawa’s daughter.
3. Yoshimaki Miura: Caused a stir in 1955 by proposing that the Imperial Palace did not belong in Tokyo according to a philosophical system which he himself invented. Many government officials discussed this claim. Also, he claimed to be the true Emperor descended from a previously unknown Hokuriku Court.
4. Toyohiko Nagahama: Claimed to be the descendant of Emperor Antoku who died in 1185, making him certainly the longest of these to get around to staking his claim. Like Kumazawa, he never took on the styles of an emperor or tried to make enemies with the Showa Emperor, but only acted as a friendly old man trying to make the truth known. He never petitioned MacArthur and was thus only famous on the little island of Ioujima, Kagoshima where he lived. Locals referred to him as “Emperor Nagahama”.
Unknown relation, Masakaze Nagahama: Claims to be next in line to the noble and majestic Nagahama lineage, and has started a society to that effect.
5. Jikouson: Founder of the political(?!) cult “Jiu“. When the Showa Emperor renounced his divinity in 1946, Jikouson claimed that the kami which had taken up residence in the Emperor, Amaterasu, had now moved into her, and the Jiu headquarters became the Imperial Palace. Consequently she invented an original Japanese era, constitution, and flag, and named her prominent followers the Ministers of Defense, Culture, etc. in a virtual cabinet. The GHQ spied on her group to ensure it was not a nationalist organization.
There are about a dozen other pretenders but none are so interesting.