Aizuri-e

Even if only a single type of blue ink was used, variations in lightness and darkness (value) could be achieved by superimposing multiple printings of parts of the design or by the application of a gradation of ink to the wooden printing block (bokashi).

[1][2] This pigment had a number of advantages over the indigo or dayflower petal dyes that were previously used to create blue.

[3] It proved to be particularly effective in expressing depth and distance, and its popularity may have been a major factor in establishing pure landscape as a new genre of ukiyo-e print.

[4] Early adopters included Hokusai in his Thirty-six Views of Mount Fuji (1830), most notably in The Great Wave off Kanagawa and Kajikazawa in Kai Province.

The theory that aizuri-e production was prompted by the 1842 sumptuary laws known as the Tenpō Reforms is no longer widely accepted.