I do not speak or read Japanese, so I'm missing out on most of the story here — but apparently this is a large collection of a child's drawings of yokai, or traditional Japanese folkloric monsters: Link one, Link two. We recently produced a series of Boing Boing tv episodes on this subject: part one, part two. (thanks, Darren Garrison)
UPDATE: Commenter FrankieZ says: "As far as I can read this is a collection of monsters from all the parts of the world, from America to Okinawa and Philippines, not only Japan. The author (he's not a kid) is not a professional drawer and his hobby is drawing monsters…"
