改善 [or Kaizen (Japanese), or Gǎishàn (Mandarin)]; improvement or change for the better, commonly referring to a continuous improvement philosophy that originated in Japan. A Kaizen approach is one that makes continuous incremental improvements to any system or process (e.g., writing a book, building a car, learning a foreign language).

This philosophy is universally applicable, and is sometimes formalized in business processes, such as PDCA, and even military strategies, such as an OODA loop, and is similar in spirit as Agile software development, and in particular Kanban.