Way of making continuous improvements by looking back and thinking about how to improve a process or personal shortcoming; the Japanese term for "self-reflection. 

In the Toyota Production System, hansei or reflection meetings are usually held at key milestones and at the end of a project. They are used to identify problems, formulate countermeasures and communicate improvements to the rest of the organization so that the same mistakes are not made again. Thus, along with kaizen and standardized work, hansei is a crucial part of an organization's learning process. It is sometimes compared to the Check phase of the Plan-Do-Check-Act improvement cycle. 

Lean Lexicon

Explanation of key Lean terms online
View the entire lexicon