Wabi-Sabi
Classical Japanese sources treat wabi and sabi as two genuinely separate concepts. Their combination into a single named aesthetic philosophy, as it is now understood worldwide, is substantially a twentieth-century construction, decisively popularised by one specific English-language book.
Leonard Koren, Wabi-Sabi for Artists, Designers, Poets & Philosophers (1994)
A Japanese aesthetic sensibility valuing imperfection, impermanence and simplicity, rooted in the tea ceremony.