With the support of JFE Systems Inc and Exa Corporation, JFE Steel has completely migrated the core computer system of the head office to an open environment. This is the first case in Japan of a complete migration of a large-scale mission-critical system with over 40 million STEPs to an open environment. Through this transition, JFE Steel will be able to respond more quickly and flexibly to customer needs and changes in the environment. Furthermore, while ensuring the reliability of system operation, it is possible to make maximum use of the abundantly accumulated data assets while significantly reducing development and operation costs.Until now, JFE Steel has been operating the core system of the head office, which is the basis for receiving and delivering steel materials and operating the management department, in a legacy environment that features high reliability, etc., in consideration of the magnitude of the impact in the event of a failure. On the other hand, since the legacy environment is built according to each manufacturer's own standards, there are few system configuration options and functional expandability, and it is difficult to utilize advanced digital technology.Therefore, based on the technological progress regarding open servers, JFE Steel has promoted the transition of the core system of the head office to the open environment. JFE Steel has adopted a hybrid cloud environment built by IBM Japan as the system migration destination. The environment has the same level of reliability as the legacy environment and can respond quickly to sudden increases in data processing volume. In addition, not only can advanced digital technology compliant with open systems be easily applied to data assets, but it is also possible to build flexible systems.With the transition to an open environment, JFE Steel is now able to respond more quickly and flexibly to customer needs and changes in the environment based on a flexible IT platform. In addition, it has become possible to further accelerate business reforms that utilize data assets, such as improving the efficiency of the entire supply chain through big data analysis of orders and deliveries of steel materials. In addition, JFE Steel anticipates merits of over one billion yen annually through lower system operating costs and more efficient development.