Regarding disruptive innovation, Christensen and Raynor (2003) assume that there are two types of customers: overshot customers in existing markets and entirely new nonconsumers in other markets. In the case of large-scale casting market within the casting industry, customers demand high quality casting surfaces. The new method of casting termed full mold casting (FMC) could only achieve low quality results compared with existing wood pattern-based sand mold casting, which had sufficiently high quality in its casting surfaces. Even in that market, however, the casting of metallic molds for automobiles had particular requirements because casting surfaces were later dealt by mold companies. Thus, customers welcomed shorter delivery times even with lower quality casting surfaces. Kimura Chuzosho Co., Ltd. first acquired certain customers who desired shorter delivery times, and then improved casting surface quality and productivity over the course of doing business with them. Eventually, they became successful in capturing more than half the market for automobile metallic mold castings. Improving the quality of casting surfaces led to market share gains for single castings used in machine tools, which demanded higher mid-range casting surface quality. Moreover, by fully mechanizing numerical control (NC) processing, the company was able to acquire market share in castings for high-end mass-produced machine tools, which demanded high-end casting surface quality and was an area that was considered difficult for FMC. In this manner, by keenly focusing on the specific requirements of their customers, Kimura had secured orders from customers who were neither nonconsumers nor overshot customers. As business continued, the company became successful in steadily improving overall quality, cost, delivery (QCD), and FMC became an example of disruptive innovation vis-à-vis existing wood pattern-based sand mold casting. The logic behind occurrences of disruptive innovation is simpler than the analysis of Christensen, Anthony, and Roth (2004): Even if a company can acquire only a small portion of customers with particular, specific requirements using QCD-related technologies, which are perhaps even toy-like in comparison with existing technologies, such company will have opportunities to improve the overall QCD as its business continues.