Kaizen (Japanese for "change for the better" or "improvement", the English translation is "continuous improvement", or "continual improvement.") is an approach to productivity improvement originating in applications of the work of American experts such as Frederick Winslow Taylor, Frank Bunker Gilbreth, Walter Shewhart, and of the War Department's Training Within Industry program by Japanese manufacturers after World War II. The development of Kaizen went hand-in-hand with that of quality control circles, but it was not limited to quality assurance.
The goals of kaizen include the elimination of waste (defined as "activities that add cost but do not add value"), just-in-time delivery, production load leveling of amount and types, standardized work, paced moving lines, right-sized equipment, etc. A closer definition of the Japanese usage of Kaizen is "to take it apart and put back together in a better way." What is taken apart is usually a process, system, product, or service.
Kaizen is a daily activity whose purpose goes beyond improvement. It is also a process that, when done correctly, humanizes the workplace, eliminates hard work (both mental and physical), and teaches people how to do rapid experiments using the scientific method and how to learn to see and eliminate waste in business processes.
"Kaizen" is the correct usage. "Kaizen event" or "kaizen blitz" are incorrect usage.
Kaizen is often misunderstood and applied incorrectly, resulting in bad outcomes including, for example, layoffs. This is called "kaiaku" - literally, "change for the worse." Layoffs are not the intent of kaizen. Instead, kaizen must be practiced in tandem with the "Respect for People" principle. Without "Respect for People," there can be no continuous improvement. Instead, the usual result is one-time gains that quickly fade.
Importantly, kaizen must operate with three principles in place: process and results (not results-only); systemic thinking (i.e. big picture, not solely the narrow view); and non-judgmental, non-blaming (because blaming is wasteful).
Everyone participates in kaizen; people of all levels in an organization, from the CEO on down, as well as external stakeholders if needed. The format for kaizen can be individual, suggestion system, small group, or large group.
The only way to truly understand the intent, meaning, and power of kaizen is through direct participation, many, many times.
History
After World War II, the occupational forces brought in American experts who were familiar with statistical control methods and with the War Department's Training Within Industry (TWI) training programs to restore a war-torn nation. TWI programs included Job Instruction (standard work) and Job Methods (process improvement). In conjunction with the Shewhart cycle taught by W. Edwards Deming, and other statistics-based methods taught by Joseph M. Juran, these became the basis of the kaizen revolution in Japan that took place in the 1950s.
Applications
The Toyota Production System is known for kaizen, where all line personnel are expected to stop their moving production line in the case of any abnormality, and suggestions for improvement are rewarded.
Kaizen often takes place one small step at a time, hence the English translation: "continuous improvement", or "continual improvement." Yet radical changes for the sake of goals, such as just in time and moving lines, also gain the full support of upper level management. Goals for kaizen workshops are intentionally set very high because there are countless examples of drastic reductions in process lead time to serve as proof of their practicality.
The cycle of kaizen activity can be defined as: standardize an operation -> measure the standardized operation (find cycle time and amount of in-process inventory) -> gauge measurements against requirements -> innovate to meet requirements and increase productivity -> standardize the new, improved operations -> continue cycle ad infinitum. This is also known as the Shewhart cycle, Deming cycle, or PDCA.
The "zen" in Kaizen emphasizes the learn-by-doing aspect of improving production. This philosophy is focused in a different direction from the "command-and-control" improvement programs of the mid-20th century. Kaizen methodology includes making changes and looking at the results, then adjusting. Large-scale preplanning and extensive project scheduling are replaced by smaller experiments in improvement, which can be rapidly adapted as new improvements are suggested.
Masaaki Imai made the term famous in his book, Kaizen: The Key to Japan's Competitive Success. An appendix to that book includes a reference to the 5S strategy of disciplined cleanup.
