This machine was developed as a computer for sophisticated scientific and engineering computations, suitable for the economic power load distribution equipment of Kansai Electric Power. It used parametrons as its main arithmetic-logic element, and primarily magnetic core for memory. It was also equipped with a magnetic drum. For data, the system used 48-bit binary words, and for instructions it used the paired order system where 2 instructions were incorporated into a single word. The address part was 13-bits, thus enabling addressing of 8,192 words of memory. The instruction set was extremely comprehensive for the time, and was comprised of 110 different types of instructions, including the floating point instructions necessary for scientific and engineering calculations.
The first machine was delivered in December 1961 to Kansai Electric Power. After that, approximately 30 machines were shipped, and at the time this was a best-selling machine for university research centers.
Hitachi created its first FORTRAN-based compiler -- called HARP (Hitachi Automatic Rapid Program) -- as software for the HIPAC 103.
Development of parametron computers by Hitachi ended with this machine.