His most famous work is probably his unmatched series of prints, Thirty-six Views of Mt. Fuji. This series is comprised of various landscapes, each of which features Mt. Fuji in varying detail. Sometimes Mt. Fuji is the center of the picture. And sometimes it's only barely visible in the background, as is the case with what is probably Hokusai's most famous single print, Beneath the Great Wave off Kanagawa. Hokusai also produced several other works, as he was famous for his obsession with his work.
However, his largest single work is the subject of this post. I'm talking of Hokusai Manga. This is a 15-volume series of books, all of which are crammed with several sketches, charicatures and cartoons from Hokusai. Hokusai dubbed his work 'manga' after the literal meaning of the word, which is 'whimsical pictures'.
None of the pictures are comics, nor do they have a plot. Each page comprises of various sketches that revolve around a certain subject (a sample of which can be viewed here). Things like fishermen, villagers, nobility, bathers, plants, wildlife, fish, insects, gods and demons, yokai, and scenes from popular ghost stories all take center stage.
Indeed, these were sketches that were made 'whimsically'. Because they are sketches and therefore lack the detail of traditional ukiyo-e, many of the pictures are charicatured. Some is even downright cartoonish. There is a definite humor to many of these. These were made for enjoyment, and it's obvious from the whimsical nature of the pictures, if not the sheer volume of them, that Hokusai definently enjoyed making this work.
The entire point behind the work was, according to Hokusai, meant to emphasize the idea behind the picture, and not detail.
Now, although it is questionable whether or not Hokusai actually invented manga (chances are he didn't), he DID coin the term 'manga'. Indeed, the cartoonish nature of many of the pictures were carried over into modern manga, and the sheer amount of various subjects covered in Hokusai's manga would eventually define the numerous subjects and genres that modern mangaka would encapsulate in their own work.
So, in essence, although Hokusai Manga contains no plot, or even sequence, the concept (a book of cartoons of varying subjects, released in serialized volumes) and execution (the sketchy, cartoonish nature of the pictures) behind it can very well be considered the precursor to modern manga.
The first volume of Hokusai Manga can be viewed here.
Take a gander at Hokusai's manga, and his other works, and come to apprecciate the magnificent artistic heritage that our modern 'whimsical pictures' has behind it.
