The aim of this article is to build new product development strategy for parts supplier. One difficulty in product development of parts suppliers is that they are faced with dilemma of choosing between product efficiency and product differentiation. To achieve efficiency, suppliers need to standardize part as much as possible. On the other hand, to achieve product differentiation, supplier need to customize part and it will decrease efficiency. Therefore, achieving both is difficult. Particularly, pars are embedded within final product and final product manufactures have strong demand for customized parts best suitable for their products. First, we conduct in-depth case analysis of Mabuchi Motor from perspective of product architecture and organization. Mabuchi specializes in miniature DC brushed motors. Mabuchi has held a more than 50% share of the worldwide market, a success driven by the company's strategy of creating common pratform for their products. We analyze how Mabuchi is able to continually meet strong demands for customized products, while maintaining high profitability. Then, we enhance product platform strategy from the case study. Finally, we discuss the validity of the strategy, based on existing findings and literature.