What is Kaizen (Continuous Improvement)?
Kaizen — Japanese for "change for the better" — is the practice of relentless, small, everyone-driven improvement: tiny experiments, measured, kept or discarded, forever. Not a quarterly initiative with a steering committee; a habit with a cadence.
In agile, the retrospective is institutionalized kaizen: every iteration, the team picks one or two process changes and actually runs them. The compounding is the magic — 1% better per sprint is 30% better per year.
Worked example
A manufacturing-software team's retrospectives produce one experiment each sprint: rotate who runs standup; auto-label PRs by module; a "no-meeting Wednesday." Individually trivial. Eighteen months of kept-or-killed experiments later, their cycle time is half the sister team's — and no single change is the reason. The habit is.