Once Hokusai was invited by the Shogun, who was the deputy ruler of the emperor, that he should paint a painting before his eyes.
When Hokusai entered the big hall, which was full of princes and Lords, he had a big paper roll brought in, which he unfolded on the floor.
Then he took a brush with blue colour in his hand and drew a broad stripe on the paper. Now he fetched a cock, whos feet had been dunked in red colour and chased him across the blue stripe. And Hokusai said to the Shogun:
"This is a picture of the Tatsuta river with autumn leaves, your Highness."