The vacuum tube-based electronic calculator was developed in 1961 by Han Man-chun (1921-1984), then professor of Yonsei University in Seoul. The device was designed to calculate high-order differential and integral equations and had been productively exploited for education and research in the area of control engineering. The calculator is known to have made a significant contribution to the development of science and technology in Korea during the 1960s and 1970s before the digital computer was introduced. The development of the device led to the publication of process of manufacturing the parts and system as a whole as well as related techniques that played an important part in laying the foundation for the development of computer-related techniques.