Kaizen is a Japanese philosophy that focuses on continuous improvement. It was developed by Masaki Imai, who is known as the "Lean Guru" and father of continuous improvement. Kaizen involves never-ending efforts for improvement by both management and workers. It was implemented in 1950 by Toyota and relies on employees identifying ways to remove waste and inefficiencies to increase efficiency. The principles of Kaizen emphasize not justifying past practices, keeping an open mind, seeing problems as opportunities, choosing simple solutions, and correcting mistakes immediately.