Research into developing a practical crossbar exchange suitable for use as a long distance relay exchange had been in progress since 1953 (Showa 28). As a result, the C8 exchange was completed in 1959 (Showa 34). This was a practical crossbar exchange suitable for use as a long distance relay exchange. The C8 crossbar exchange became the standard long distance relay exchange and was installed in all major cities in the country including Tokyo. The exchange contributed to improving the capability of long distance calling. The exchange also made a significant contribution to the achievement, in 1967 (Showa 42), of a direct dialing service between all cities containing a prefectural office.