What is Kaizen (改善)?

Kaizen is a Japanese concept for continuous improvement, derived from the words kai (change) and zen (better). Kaizen embodies the belief that every process, every day, at every level of the organization, can be improved, and that this improvement is the responsibility of everyone involved in the process.

Kaizen is therefore more than just a method: it is a mindset. Whereas Western improvement initiatives are often set up as defined projects with a clear beginning and end, kaizen is a continuous process with no endpoint. Small, incremental improvements, made day after day by the people who know the work, eventually lead to fundamental change.

The Relationship with Standardization
‍Kaizenand standardized work are inextricably linked. A standard is not the end point of improvement, but the starting point: you improve an existing work method, establish the improvement as a new standard, and start over. Without a standard, there is no basis for improvement; without Kaizen, a standard becomes frozen in bureaucracy. This cycle directly follows the PDCA logic: Plan, Do, Check, Act.

Two Levels of Kaizen
‍Kaizentakes place on two complementary levels:

System or flow kaizen focuses on the entire value stream: the complete sequence of activities from raw materials to the customer. This is kaizen for management: it involves making strategic decisions about which flows to improve, how processes are interconnected, and where the greatest sources of waste lie within the system. Value stream mapping is a widely used tool for initiating and guiding flow kaizen.

Process Kaizen focuses on individual processes and workstations. This is Kaizen for work teams and team leaders: it involves eliminating waste in day-to-day work, improving work sequences, and removing bottlenecks on the shop floor.

Kaizen in Practice
‍InWestern Lean, kaizen is often implemented in the form of a Kaizen event: an intensive three- to five-day improvement workshop in which a multidisciplinary team focuses entirely on improving a single specific process or work area. A kaizen event has a clear scope, a measurable goal, and leads to the immediate implementation of improvements on the shop floor.

Although kaizen events are valuable, Lean emphasize that they are no substitute for a daily kaizen culture. Structural improvement does not result from periodic workshops, but from the habit of continuous improvement that is embedded in the daily work of everyone in the organization.

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