Abstract
Multiple prior studies stress that continued Kaizen activity is conducive to building and maintaining competitive advantages of manufacturing companies. Meanwhile, it remains unclear as to what kind of management factors may exert impact on sustainment of Kaizen activity. This paper discusses a study conducted on the cases of two manufacturing lines, where such activity has been continued for more than ten years. At first, it was discovered that study period was divided into different periods. It was also found out that 'standstill conditions' which prevent smooth progress of activity exist in many periods, and that such conditions are hard to avoid. The study went on to categorize progress of activity in each period into different patterns, including at which points standstill conditions occurred, thereby, circumstances of standstill conditions were made clear. This paper verified a detailed process of Kaizen activity development in each period and the relationship between that detailed process and points of occurrence of standstill conditions. Thought was also given to factors and actions for smooth development, and effects brought about by overcoming such challenges. Lastly, consideration was given to the future perspectives of the study for elucidating how better Kaizen activity may be managed for continuation.