“Kaizen”. One of the most popular Japanese word that is known inside operations management. Usually, it is translated as “Continuous improvement” but is that the meaning? It is a little complicated so I used Japanese dictionaries to dig deeper.
1. “Kaizen” is not Toyota's original word. It was born about two hundred years ago. When this word was born, it had a twin. The word is “Kaiaku （改悪）” meaning “change for the worse”. (Ohno used this word once in his book “Workplace management”.) Thinking of these words as a set, I believe they used to question or reflect if this was a good or bad change.
2. Just because it is a relatively new word, if there is no foundation, I doubt that the word will survive. In Buddhism, there is a lesson called “Every day, do one Good act（一日一善）” very similar to daily Kaizen（日々改善）. This Buddhism lesson is asking to practice six (not seven) types of a good act.
Fuse （布施）= Be kind
Jikai （持戒）= Your behavior & words match
Ninniku （忍辱）= Patience
Shoujin （精進）= Effort
Zenjyou （禅定）= Reflection
Tie （智慧）= Learning
It does look like what a good TPS coach will try to make you go through.
3. In Japanese, there is a word called Kairyou （改良）. Comparing Kaizen & Kairyou is a typical dialog between coach & student in our world. A typical definition of these two words will be following;
Kaizen = improvement of abstract things (Ex. Productivity etc.)
Kairyou = improvement of concrete real things (Product, Machine, etc.)
By looking at these typical Japanese explanations, anybody who received coaching from a good TPS coach will puzzle. “Didn’t my coach say implement Kaizen = make real changes on the shop floor every day?” I think this is because the meaning of “Kaizen” is slightly different in Toyota. The word “Kairyou” has existed inside Toyota since its foundation. The fact is the Toyoda family talks about the importance of “Kairyou” on their product & machines. Ohno was not happy with just that thinking. He wanted to speed up more. He wanted more people (especially the shop floor managers) to take more ownership. He wanted more freedom. That is the reason why Ohno started using Kaizen. And it is important to note such transition from Kairyou to Kaizen because it is part of Kaizen's thinking to convert traditionally Kairyou activity into Kaizen. Or improvement or improvement activity itself.