Kaizen in Japan versus the English-Speaking World

In a discussion of the economic justification of Kaizen in the  TPS + 1 ENGINEERING discussion group on LinkedInKenyon Denning asked what Kaizen is and is not, and pointed to the English dictionary definitions on the web. Why look up a Japanese technical term in a general-purpose English dictionary? We should focus instead on what Kaizen means as a technical term in Japan.

If we are using it to mean something else, we are misleading our audiences, because they assume that you are talking about the approach that has contributed to the success of companies like Toyota, Honda, Matsushita, Kawasaki, and others, and that is the only reason they are listening. And the problem is that we are indeed using the term differently. The most common usage is in “Kaizen Events,” a project management format developed in the US that does not actually implement Kaizen. The popularity of Kaizen Events crowds out the genuine Kaizen from practically all the Lean implementation programs in the US. To see it in the US, your best bet is to visit Japanese transplant auto factories.

Over the past 35 years, Kaizen has become an English word. Among other data, Google about gives you the following chart of the use of Kaizen in English over time.  This chart based on a search of Google Books by ngram viewer. After rising steadily from 1978 to 2000, it has been holding steady through 2008, the latest point provided, at 0.33 words/million.

Use of Kaizen in English 1970-2008
Occurrences of “Kaizen” as a percentage of all words in English-language books

By comparison, for the same year, the following table gives Google’s occurrence rates for a few selected terms. I assume Google compares single words with other single words but I am not sure what it does with a 2-gram like “Lean manufacturing” that is used in speech like a single word.

Kaizen occurrences compared


The available on-line definitions for Kaizen in English dictionaries are as follows:

  1. Random House (2013):
    • A business philosophy or system that is based on making positive changes on a regular basis, as to improve productivity.
    • An approach to one’s personal or social life that focuses on continuous improvement.
    • Origin: < Japanese: literally, ‘continuous improvement’
  2. Collins Complete & Unabridged 10th Edition (2009):
    • A philosophy of continuous improvement of working practices that underlies total quality management and just-in-time business techniques
  3. Dictionary.com’s 21st Century Lexicon:
    • Japanese for continuous and incremental improvement, a business philosophy about working practices and efficiency; improvement in productivity or performance.
    • Etymology: Japanese ‘change for the better’

By contrast, following are a few Japanese views on the subject:

  1. The most common general language dictionary used in Japan is the Kojien (広辞苑). Its definition of Kaizen (改善) is “the act of making a bad place good again” (悪いところを改めてよくすること) and the example given is “improving the treatment” (待遇を改善する). The opposite is “changing for the worse” (改悪, Kaiaku).
  2. In a technical context, author Bunji Tozawa defines Kaizen as “changes in methods to make the work easier, conceived and implemented by those who do the work.”
  3. Another Japanese author to emphasize Kaizen is Masaaki Imai, who defines it as  “ongoing improvement involving everybody, without spending much money.” 
  4. In 1985, the Japanese Factory Management monthly (工場管理) issued a Dictionary of Shop Floor Kaizen (現場を改善する辞典), which managed not to contain a definition for “Kaizen,” but, like Tozawa and Imai, it emphasized that kaizen is something everybody does, to make the work easier to do, produce better quality output faster and cheaper, while making the workplace safer. The list covers every known dimension of manufacturing performance except morale, which improves as by-product.

To Tozawa, each discrete change is a Kaizen;  to Imai, Kaizen is the process by which these improvements are made on a continuing basis. I have not seen an explicit emphasis in Tozawa’s writings about Kaizens being cheap, but it is implicit in the idea that the improvements are done by the people who do the work. Cheap, however, does not mean free, and Kaizen activities commonly involve giving individuals or teams license to spend a few hundred dollars at a hardware store for a project, but a $50K investment would be outside the scope of Kaizen.

None of the English dictionaries says anything about changes being made in work methods, by the people who do the work, and requiring little or no investment. In none of the Japanese descriptions of Kaizen does it rise to the level of a “business philosophy.” The nature of Kaizen is best shown through examples, and I would like to share one that struck me as a particularly vivid illustration.

Traditional Japanese squat toilets on Shinkansen trains
Traditional Japanese squat toilets on Shinkansen trains
Standard train toilets
Standard train toilets

About 15 years ago, Kojo Kanri focused an issue on Kaizen in the kind of dirty jobs that do not receive much management attention (泥臭い改善, dorokusai kaizen). There was in particular a story about a circle of high-speed train janitors who were tired of cleaning the same toilets 8 times a day. These trains were equipped with traditional, Japanese squat toilets that international passengers did not know how to use and messed up as a result.

One obvious solution was to replace these toilets with the worldwide standard. It would have been no hardship for the Japanese passengers, because this style is already used in 90% of homes and work places in Japan. But replacing these toilets in 100 16-carriage trains could not have been done quickly, and was an investment beyond the scope of Kaizen.

So the janitors took a number of simpler steps, and measured the results in terms of the number of required cleanings per toilet per day. This included posting some graphic explanations on how to use the equipment, painting outlines of where users should place their feet, and finally materializing the right locations with rubber pads to make it awkward to place your feet anywhere else. At the end of the project, the required cleanings were down to one toilet per day.

Earlier posts on Kaizen in this blog include the following: