Lean Manufacturing and Six Sigma Definitions

Glossary terms, history, people and definitions about Lean and Six Sigma

Sakichi Toyoda

Sakichi Toyoda (February 14, 1867 – October 30, 1930) is referred to as the “King of Japanese Inventors”.  He started the Toyoda family companies, starting with an engineering manufacturing company called the Toyoda Automatic Loom Works in 1926. It earned him the moniker of father of the Japanese industrial revolution. His son, Kiichiro Toyoda, would later establish the world’s largest automaker, Toyota.

After noticing the struggle his mother had with looms, through trial and error, he invented his most famous invention, the automatic power loom. It required only one hand to operate instead of two, which improved quality and increased efficiency by 40-50%. This led to the principle of Jidoka (autonomous automation) and error proofing.

He is also credited with developing the concept of 5 Why’s, along with Taiichi Ohno and Isao Kato.

When a problem occurs, ask “why” five times to try to find the source of the problem, then put into place something to prevent the problem from recurring.

An example of 5 Why’s is shared in the book, Lean Impact: How to Innovate for Radically Greater Social Good

  • Why is the orangutan population declining?
  • Their rainforest habitat has been reduced over the years. Why?
  • People are cutting down the rainforests. Why?
  • They need to raise money quickly to send family member to expensive hospitals far away. Why?
  • There is no local or affordable health clinics. Why?
  • Their area is poor, remote and often neglected by private and government organizations

This concept is used today as part of applying lean methodologies to solve problems, improve quality, and reduce costs.

Sakichi Toyoda passed away in October 1930, having devoted his 63 years to invention. The top management of Toyoda companies assembled the “Toyoda Precepts” to clearly crystallize his spirit.

  • Always be faithful to your duties, thereby contributing to the Company and to the overall good.
  • Always be studious and creative, striving to stay ahead of the times.
  • Always be practical and avoid frivolousness.
  • Always strive to build a homelike atmosphere at work that is warm and friendly.
  • Always have respect for spiritual matters, and remember to be grateful at all times.



  • Kiichiro Toyoda




Additional Resources