Takeshi Yamamoto, an unemployed man in Gifu Prefecture has been charged with posting the threat, which caused a police alert on an anonymous bulletin board, Kyodo News reported Saturday.

The man reportedly has admitted to posting the message, ''I will kill the crown prince,'' through his home computer Aug. 13. But he now maintains it was just a hoax.

Police allege Yamamoto also threatened to kill a company president, as well as writing of his general unhappiness with Japanese society.