Contents

• What's New
• Japan Standard Time (JST)
• Transmission Information
• What we do
• JJY
• Time Dissemination Service
• FAQs and Data
• Space-Time Standards Laboratory
  

Information

• No leap second will be introduced on January 1, 2024.　(2023/7/10)
  （No leap second was introduced on July 1, 2023.）
• Japan standard time distribution service over analog telephone lines (Telephone JJY) ends March 31, 2024. (2023/3/15)
• The way to register using the Hikari-telephone JJY has changed.　(2022/9/1)
  

Topics

• Press Release： World's first use of the "Optical lattice clock" to maintain National standard time.
  〜Synchronization with UTC became possible only with the clock of NICT〜（2022/6/10）
  

LF Standard Time and Frequency Transmission Station

• Periodic maintenance of facilities in the LF Standard Time and Frequency Transmission Stations will be performed. (Links to a Japanese page) (2023/8/29)
• Transmission Information of JJY signals (Japanese version only)

Contents

Welcome to Japan Standard Time (JST) Group. JST Group plays an important role in the Generation, Comparison, and Dissemination of Japan Standard Time and Frequency standard. Please choose the contents you'd like to use.

	What's New
	What we do
	The Information of Standard-time and Frequency-signal Emission (JJY) (The users of radio wave clock see here for more information, please)
	Time Dissemination Service (NTP,TEL-JJY,Time Business,calibration)
	FAQs and Data

Contact Us

Please contact us if you have any questions, comments, corrections, or suggestions.

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