„All I have produced before the age of seventy is not worth taking into account. At seventy-three I have learned a little about the real structure of nature, of animals, plants, trees, birds, fishes and insects. In consequence when I am eighty, I shall have made still more progress. At ninety I shall penetrate the mystery of things; at one hundred I shall certainly have reached a marvelous stage; and when I am a hundred and ten, everything I do, be it a dot or a line, will be alive. I beg those who live as long as I to see if I do not keep my word. Written at the age of seventy five by me, once Hokusai, today Gwakyo Rojin, the old man mad about drawing.“
On one of his pseudonom, Gyakyo Rojin. He may have said the above in his late life definitely, since he began to use the name Gwakyo Rojin in 1843.