Very simple Japanese. I read this book because I watched the movie based very loosely on it. The book is not a story, though--it's the first in a series of guidebooks on Yokai in Japan, and how to deal with said Yokai without getting killed. Each Yokai is given a danger rating and the ways it attacks and ways to escape from the monsters without getting killed. This one is particularly about monsters of the sea, like Umibouzu, or the Japanese version of mermaids, and a ghost ship. Lots of colorful illustrations. None of these monsters appeared in the movie, though--the ones in the movie came from other books in the series.