Lean Manufacturing and Six Sigma Definitions

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


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Japanese word that translates to “self-reflection.” To recognize and reflect on mistakes, and to commit to take appropriate action to avoid re-occurrence.

Toyota uses a hansei-kai, or reflection meeting to review a project or activity, regardless if it was a success or failure. It helps to identify failures experienced along the way, and create clear plans for future efforts.

An inability to identify issues is usually seen as an indication that you did not stretch to meet or exceed expectations, that you were not sufficiently critical or objective in your analysis, or that you lack modesty and humility. Within the process, no problem is itself a problem.

The following is an excerpt from the old website Superfactory.com

“Han” means to change, turn over, or turn upside down. “Sei” means to look back upon, review, and examine oneself. The generally accepted American translation for hansei is reflection – although many argue that reflection does not do the concept justice because it sounds like a simple intellectual exercise, whereas in Japan hansei is also a very emotional and introspective experience. 

The concept of hansei is probably one of the greatest differentiators between American and Japanese culture. In the hansei process, the emphasis is on what went wrong and on creating clear plans for ensuring that it does not reoccur – and this is done constantly and consistently. At Toyota, even if you do a project successfully, there is still a hansei-kai (reflection meeting) to review what went wrong. If a manager or engineer claims that there were not any problems with the project, they will be reminded that “no problem is a problem” – in other words, you haven’t objectively and critically evaluated the project to find opportunities for improvement.

Many Americans have a very difficult time with the constant critiques and focus on the negative (opportunities for improvement). Andy Lund, a Program Manager at Toyota, explains it this way; “people who have not been to Japan may not understand that the objective is not to hurt that individual but to help that individual improve – not to hurt the program but to show flaws to improve the next program. If you understand that deeply, you can get through that constructive criticism. No matter how good a program or a presentation someone makes, we believe there is always something that can be improved, so we feel it is our obligation. It is not an ‘obligatory negative’ but an obligatory opportunity to improve – it is the heart of kaizen

There are of course different levels of hansei ranging from frequent and quick reflections on actions taken, tasks completed, observations, lessons-learned, etc. to brutally honest and factual reviews of project performance and results, to very deep and introspective reflection on oneself. Toyota is very disciplined about conducting hansei-kai (reflection meetings) at key project milestones, when critical decisions are made, and at the completion of projects. They are also very disciplined about taking the time to reflect on the activities of a given day – it is simply part of their culture – it is a necessary element to achieving their goal of continuously improving and pursuing perfection.

Hansei is a necessary element to being a “learning organization”. It is also an essential part of kaizen (continuous improvement) – you can think of it as the “check” phase in Deming’s Plan-Do-Check-Act (PDCA) cycle. You could also argue that it should be considered a part of the “act” phase since hansei requires that you change the process or your behavior based on your reflection. The challenge is to be very disciplined about reflection and learning at all levels, and to create a culture that fully supports it. According to a Japanese Toyota Sensei, American managers and engineers find it very difficult to take the time for real hansei – so they simply go through a superficial review of the facts & data (if they even do that) and move on to the next job or project. The Toyota Production System (TPS) is often referred to as the Thinking Production System (TPS) – primarily due to their discipline and diligence with hansei.

Hansei has three elements:

1. The individual must recognize that there is a problem – a gap between expectations and achievement – and be open to negative feedback.

2. The individual must voluntarily take personal responsibility and feel deep regret.

3. The individual must commit to a specific course of action to improve.

Continual reflection is an expectation of the Toyota Production System.



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