In 1953 it is determined that Japan's needs for automatic switching equipment will be best met by the use of crossbar switching, which uses shared control circuits called directors and markers. Crossbar switching equipment is imported from the U.S. in 1955 and installed in exchanges in the Annaka and Kurakano offices in the Takasaki area. Further study at the Electrical Communications Research Center results in the development of an omproved crossbar switch using a wire spring relay, and in Showa 31(1956) the first Japanese-made crossbar switching equipment is installed on an experimental basis in the Miwa exchange in Tochigi Prefecture.

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