Kaizen is the Japanese name for continuous improvement. As such it is central to Lean operations. It brings together several of the tools and techniques described in this book plus a few besides. The word originates from Maasaki Imai who wrote a book of the same name and made Kaizen popular in the West. Although a registered name of the Kaizen Institute, the word is now widely used and understood and has appeared in the English dictionary.

According to Imai, Kaizen comprises several elements. Kaizen is both a philosophy and a set of tools.