The Japanese word 改善 specifically means "Incremental and continuous improvement". 改善 is composed of the kanji改 (read kai) meaning "change; renew; amend; reformation" and 善 (read zen) meaning "good; virtuous".
This design reminds us that improvement really is a continuous process and Perfection is never achieved. R. H. Blyth in Zen and Zen Classics Volume One explains a fundamental of Zen Buddhism as "Holding to the One is not Truth." There is no Perfect, there is only the journey.
In his book The Japanese Have a Word for It: The Complete Guide to Japanese Thought and Culture Boye Lafayette De Mente uses the translation of kaizen as "Nothing is Ever Good Enough". He writes "Kai zen literally means 'continuous improvement,' and is a concept that has permeated Japanese culture since ancient times. It means, simply, that the Japanese are driven by an innate urge to continuously strive to improve both the form of the things they make as well as the manufacturing technology and process." He went on to write, "The historical factor that gave rise to the kai zen concept was the master-apprentice approach that was applied throughout the arts and crafts, from the making of pottery and bamboo baskets to the painting of wall scrolls. As the centuries passed, acceptable standards became higher and higher until finally even the most mundane article was expected to be a work of art."
