What is 20Keys?

Iwao Kobayashi, in 1988 published a book explaining 20 keys to workplace improvement. They all must be considered in order to achieve continuous improvement. These 20 keys are arranged in a circle that shows the relations between the keys and their influence on the three main factors explained previously: quality, cost, and lead time.

The arrangement in the circle is not categorical, and some keys offer benefits in more than one factor. There are four keys outside the circle. Three of them (keys 1, 2, and 3) must be implemented before the rest, and key 20 is the result of implementing the other 19 keys.