Jindai moji (神代文字, "Characters from the Age of the Gods") are one of the legends of Japanese pre-war history: spurious syllabaries invented, promoted, and possibly even believed in by people who just could not accept the idea that Japan needed China's help to learn how to write.

And here is an encyclopedic page with samples out the wazoo. The introduction explains the obvious problem with all known jindai moji: they are clearly based on the modern Japanese phonetic system rather than its eight-vowelled ancestor as would be expected -- nay, required -- of any syllabary in use before the Heian period.

(There is also the obvious question of why any Japanese person in their right mind would voluntarily adopt the thrice-accursed Manyōgana system if they already had a perfectly functional native syllabary.)

Let us peruse the examples:

• The laughably inept Ainu moji fail because they match the phonology of (modern) Japanese, not that of Ainu.
• The Ahiru moji are a sadly transparent copy of Hangul, right down to the unnecessary detail of copying the use of the /N/ circle to mean "no initial consonant". The cursive version is particularly insane.
• The Sanka moji are a reinvention of kanji, which is like setting out to counterfeit some banknotes but then deciding that your first task should be to meticulously construct a copy of the wallet you found them in.

My absolute favorites, though, are the Katakamuna moji, allegedly invented and used by the antediluvian Katakamuna civilization, which is in turn attested in the Katakamuna documents, which were probably fabricated by some joker in the Edo period before being discovered by NARASAKI Kōgetsu in 1949, allegedly through the agency of a mysterious man named HIRA Tōji, who claimed to be a representative of Katakamuna Shrine, the existence of which remains to be demonstrated.

"Mon père était prêtre de notre temple Shintoïste," Hira said (according to this French site.) "Notre famille a gardé ces documents de génération en génération, mais personne n'en connaît la signification." (The remote possibility that Hira was telling the truth and his famille had remained in a state of suckerdom de génération en génération makes this story worth repeating.)

Here are some fonts you can use to make your own fraudulent documents. Just be sure to tell the little girl's papa if you do.