Notan — Japanese for "light-dark" — is the design discipline of balancing masses of black and white with no midtone between them. Brushed in sumi ink on white washi, a notan study is fundamentally reversible: a yin-yang interchange where positive and negative carry equal weight. The honest ground is the black field with white shapes cut from it, not a defaulted white page.

This system distills that two-value rigor into an interface language. Components read as flat white masses cut from a carbon-black ground, their edges carrying dry-brush character. No gradients, no grays, no color — only the patient negotiation of light against dark.