In this paper, we first ask how the performance of Japanese engineers is determined. To answer this, we construct a determination model based on the hearing of 9 leading manufacturing companies in Japan. We then ask how much this model can explain the variation of performance as well as the rewards of the performance. To answer this question, we fitted this model for the unique dataset mentioned above. The summary and discussion of the multivariate analysis follows. In the following section we discuss the changing workplace environments as well as the macro environment, including labor market and the product market. We argue that those changes are in general counter-productive for sustaining the high performance of the Japanese engineers. We then conclude the paper by discussing the policy implications as well as these for the management.