Parametron
Japan has been good at computers for a long time.
In 1954, Eiichi Goto invented the parametron, a logic device leveraging nonlinear parametric oscillation with two ferrite cores [and] in 1957, Goto led the development of the PC-1, a pioneering fully programmable stored-program computer powered by 4,200 parametrons. … Unlike the complex, maintenance-intensive vacuum tube computers of the era (vacuum tubes had relatively short lifetime compared with other circuit element, thus the necessity of replacement of a few vacuum tubes a day for constant operation), the PC-1 achieved high reliability with fewer components, low power consumption, and exceptional fault tolerance, ensuring sustained operation in a university laboratory environment.
Also, necessity…
Why did you create parametron? “At the time, there were no computers in Japan. So we decided to make one at the Takahasi Laboratory at the University of Tokyo. But the university’s research budget was not enough. At the time, vacuum tubes cost 1,000 yen each, and transistors cost 8,000 yen each. Also, vacuum tubes wear out quickly. Transistors were still unstable. In comparison, ferrite cores, which had long been familiar in, say radio circuit construction, cost just 5 yen each. So I thought, why not use ferrite cores as the material? Ferrite cores are a stable material, and since they are made of pottery, they don’t break if you make them right the first time.”
Via Hacker News.