John Locke said in "Two Treatises of Government" (1689), that myth - such as the story that Adam, the ancestor of kings and queens, received the right to theocracy from God - doesn't apply to real politics.
In 1824, when a British whaling ship - whose empire had already colonised the Qing Dynasty in the Opium War - washed ashore on the Otsu beach of the Japanese states, Aizawa Yasushi, the ship's translator, wrote "The New Theory" (『新論』) the following year - explaining the need for self-defence as anti-colonialism by a unified state under the Emperor (Pope), who was a mythical authority.
He said in the essay,
Our divine land is the place where the sun rises and where the primordial energy originates.This became a theory to rebuild the Operating System of the nation from the shogunate.
The heirs of the Great Sun have occupied the imperial throne from generation to generation without change since time immemorial.
Japan's position at the apex of the earth makes it the standard for the nations of the world. Indeed, it casts its light over the world, and the distance that the shining imperial influence reaches knows no limit.
Today, the foreign barbarians of the West, the lowly organs of the legs and feet of the world, are rushing across the seas, trampling on other countries and daring to overthrow the noble nations with their squinting eyes and limping feet. What arrogance!
-- Aizawa Yasushi "The New Theory" (1825)
(会沢安『新論』1825年)
What was a shogunate? It was a real political institution in Japan. Simply put - if on myth era, emperors who invaded Japan and said ancestor goddess Amaterasu's children, they had the legitimacy of theocracy as believers in Shinto: for example Mr. Rintaro Ishibashi who was a member of the House of Representatives elected from the Hiroshima constituency.
But in the Heian period, the imperial family made money politics *1, became shogunate like parliamentary politics in Britain. We call it shogunate.
Actually, it worked well after Minamoto-no-Yoritomo became syogun at the imperial court.
The Shogunate OS also worked during the Mongol invasions of Japan, but then the Emperor OS was incompetent and could do almost all nothing. Fujiwara no Teika, a member of the high court nobility monopolised by the Emperor's blood, said,
'I am not so barbaric as to raise a flag with the Emperor's chrysanthemum crest to fight barbaric foreigners.'These historical facts are enough to explain the empty myths left behind after the Second World War, when the Allies, including Britain and the United States, maintained the Emperor under the guise of a "nominal monarch" style.
-- Fujiwara-no-Teika "Bright Moon Record"(1180-1235)
「紅旗征戎非吾事」
――藤原定家『明月記』（1180年から1235年）
For example, a Dr. Cambridge loves the Ise Shrine, honours the Emperor's ancestral goddess, and is somewhat sympathetic to the male lineage supremacy (a post-Meiji era belief includes sexism) on which their mythology is based.
Of course, even to a mere neuroscientist, there is an obvious logical inconsistency in this, since the male's Y chromosome genes of the Emperor are not directly linked to the ancestral goddess Amaterasu.
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Reference:
1) 『改訂新版 世界大百科事典』「平安時代」「社会、経済」の項
("Revised Encyclopaedia of the World", Heian Period, 'Society, Economy'.)
