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Mission of Japan Standard Time Group

New Initiatives for an IT Society

The concept of incorporating precise time into advanced information society is eferred to as new words “time business,” which mainly consists of “time dissemination” and “time authentication” business. The IT community has been encouraged to adopt precise time; e.g., as a timestamp. A Japanese law concerning reliability of electronic documents (commonly called "e-documents law") which came into effect in April 2005, requires time stamps to be put on electronic documents to certify that they have not been altered, and it is inevitable for precise time information to be used for the time stamps. In response to the needs of society, the JSTG began distributing Japan Standard Time, which is internationally traceable and widely available in the general public, in an easy-to-use format for issuing time stamps in February 2005. This has made it possible to use precisely and socially authorized electronic time information.

At the beginning of this service, time stamps were issued only through a certification system by a voluntary organization. However, in line with trends in other countries, a national certification system was launched in July 2021.
As shown in the figure below, National Institute of Information and Communications Technology, as a National Time Authority (NTA), distributes Japan Standard Time (UTC(NICT)) to the authorized time certification service providers by publishing the measurement data obtained by the common view method using GPS satellites on its websites (https://tb.nict.go.jp) and other methods. The authorized providers maintain their timescale so that the difference between their own clocks and Japan Standard Time is within one second. As a result, a system has been built in which time traceable to Japan Standard Time is distributed (time stamps are provided) to users.

In addition to the common view method using GPS satellites, Japan Standard Time is also distributed using the Telephone JJY, NTP, optical telephone JJY, and JJY by the JSTG.>
And the JSTG has promoted the use of traceability chains of UTC (NICT) to the authorized provider and the structure of the time dissemination and the audit carried out by the authorized provider. Technical requirements for the authorized provider have been established in Japanese Industrial Standards (JIS X 5094) and also established in ISO/IEC 18014-4 by the International Organization for Standardization.

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