One of the most beloved Japanology memes overseas involves the word kaizen (or Kaizen to some). Here's the definition from the New Oxford American Dictionary:

kaizen |ˈkaɪzən|
noun: a Japanese business philosophy of continuous improvement of working practices, personal efficiency, etc.

That sometimes gets further embellished by eager writers who extend kaizen to carry continuous improvement out of the business realm, and "throughout all aspects of life", per one definition I've seen. Whatever the specifics, what you'll find in common across all definitions is that kaizen is a Japanese word for "a Japanese philosophy of continuous improvement".

Unfortunately, that's wrong.

What's it really mean?

Jump down to "The wrap" at the end of this article if you want the quick low-down. Otherwise, here's the full story, starting with the real meaning of the Japanese word kaizen from the Shogakukan Dictionary:

かい‐ぜん【改善】〘名〙悪いところを改めてよくすること。

Direct translation:

kaizen (改善) noun: The act of making bad points better.

My literal translation is a wee clumsy; warui tokoro ("bad points/areas") could be more neatly translated as "defects" or "flaws". In any case, dictionaries from Sanseido and Oubunsha, as well as the massive and authoritative Koujien, give an identical definition, which points to a one-word, spot-on English translation: "improvement". Indeed, Japanese-English dictionaries, such as the Progressive or Sanseido dictionaries, translate kaizen into English using the single word "improvement". Period. 

Not continuous

Note what's missing in the Japanese definition: both the qualifier "continuous" and anything to do with "Japanese philosophy". Kaizen is derived from Chinese, and its characters appear without change in Chinese (gǎi shàn), Korean (ge sun) and Japanese (kaizen). The word has the same mundane meaning of "improvement" in all of these languages. This kaizen is improvement one time or a million times, momentarily or continuously; it doesn't matter. Contrary to modern mythology, there is no meaning of "continuous" built into kaizen.

That said, one certainly can perform kaizen on a continuous basis, and that's what happened in Japan, right? Well, sure, some firms and sectors of industry in Japan have made an excellent practice of continuous improvement, creating effective management systems to generate, capture, and review improvements in never-ending cycles. Toyota is the best-known example. After all, isn't "kaizen" the very name of that company's game-changing management methods?

Not quite. Toyota's overall system of techniques for production management goes by the prosaic name Toyota Production System (Toyota seisan houshiki). The system rests upon a number of core principles, one of which is indeed labeled kaizen - which for purposes of Toyota's usage (or generally, any manufacturing usage) certainly does mean continuous improvement. My point is this: "Continuous" here is a logical extension of the word's use in manufacturing, not a part of the word's core definition itself. In the same way, another principle of the Toyota Production System, jidouka (automation), logically implies continuous automation. Likewise, your resolution to get more exercise logically implies continuous efforts to do so, not a single set of push-ups. Yet those logical implications don't make "continuous" an integral part of the definitions of "automation" or "exercise".

So if "continuous" isn't part of the definition of kaizen, why would Toyota choose the word to wrap up its goals and processes aimed at continuous improvement? Because for a short single-word name, kaizen is the only real choice - as there is no magical Japanese word for "continuous improvement".

Not Japanese

Moving along: Whether continuous or not, what's Japanese about "improvement"? Nothing. It feels silly to have to point this out, but companies, organizations, and people everywhere engage in improvement, in all areas of human endeavor. From the wheel to the jumbo jet, from superstition to science, from warring tribes to democracies, it's all improvement, little by little, never ending. Continuous improvement is integral to all of human history, past and future.

Japan included, of course. Some of its industrial kaizen has been really spectacular, such as the improvements Japanese automakers effected in their products. Endeavors in other sectors in Japan, such as hospital practices and efficiency in the construction and certain retail sectors (to toss out a couple of examples), haven't been so swift with the kaizen and are the envy of no one. The point is that there is not, and cannot be, anything "Japanese" about concepts as universally human as "improvement" or "continuous improvement".

The closest you could get with a Japan-centric tack is specifying kaizen in the context of specific industrial management techniques advanced in Japan and labeled with the word. Yet even there the national designation gets fishy. Any authority on the topic, inside Japan or outside, will cheerfully acknowledge that the whole "industrial kaizen" ball got rolling in Japan with management and quality control techniques developed and taught by outsiders like W. E. Deming and J. M. Juran.

A new definition: kaizen vs Kaizen

So we've got the definition of kaizen all wrong, and we should stop using the word, right? No! This is an important point: If folks have coined a new English word meaning "continuous improvement", then so be it! This word Kaizen (I'll capitalize it to distinguish it from kaizen) may differ from its Japanese ancestor, but that's how language rolls. Long live Kaizen!

All right, then, this new English word covers the concept of "continuous improvement"; what else is in its definition? Is Kaizen a management term referring to specific bottom-up processes for ongoing, cyclical, and qualitative identification, implementation, and review of improvements in an industrial setting? Or can it be applied more broadly to any business setting? Or does Kaizen expand beyond the workplace to improvements all throughout life?

I'll leave that to those who make use of (and continuously improve?) the word. But one plea, dear reader: Even with flexible modern English definitions of Kaizen, please don't include - or allow others to include! - the silly bit about "a Japanese philosophy". Whether your Kaizen refers to "continuous improvement" in all areas of human endeavor, or only to improvement in all areas of business endeavors, or even narrowly to very specific management practices exemplified by systems within Toyota which are based upon the teachings of American experts and tagged with a mundane Chinese-derived word, it should be clear that labeling the concept as "a Japanese philosophy" is just goofy.

(Incidentally, I wonder how the word kaizen/Kaizen first came to English. Maybe in the same apocryphal way as "kangaroo". Like this:

American management guru: "Wow, the work you've done in this auto plant is amazing. Please, you must tell me, what is the Ancient Oriental Secret behind it all?"

Japanese factory guys: "Hmm? Nothing, really... just 'kaizen' – that is, we just make improvements when we see someth..."

Guru: "Astounding! I must tell the world of this mystical Asian 'Ky-Zen' philosophy! If only the Western world is ready for it! My book will prepare them - coming soon, just $29.99!"

Factory guys: <look at each other, scratch heads>  )

Semi-joking tangents aside, what's really interesting is this: Modern Japanese itself has a new word kaizen - written with katakana (カイゼン) to distinguish it from the mundane kaizen (改善) - to cover this newfangled concept of "philosophy of continuous improvement". In Japan as everywhere, people gotta keep up with the latest in global trendy management terms!

The wrap

A summary:

You might use the Japanese word kaizen as Toyota does, as the name for a Toyota management principle covering a number of techniques aimed at continuous fostering of improvements in products and processes. Or you may use Kaizen (my recommended capitalization) as a new English word with a similar definition, or perhaps with the simpler definition of "continuous improvement", which you might further constrain to usage in business or industrial settings.

There's no problem with those usages. Just for the record, though, there is no Japanese word with the inherent meaning of "continuous improvement"; contrary to myth, the everyday Japanese word kaizen means only "improvement" in the same generic and mundane sense as the English word.

Similarly, while we can point out specific improvement-related techniques that were developed in Toyota or other workplaces in Japan, there is no basis to claim existence of a unique "Japanese philosophy of continuous improvement", under any name. That's pure modern mythology.

That about covers it. For the moment, in any case; kaizen has proved to be a somewhat tricky and slippery word to dissect. I'll happily take corrections where warranted, and engage in continuous improvement of my own. If there's a defect in my output above, jump to the comments and halt my assembly line. I'll procure some fixes, Just In Time!