Dear Nick, Thank you for your interest. We will respond to your inquiry. It is said that corresponding summer time was performed by instruction of the GHQ: General Headquarters (office of the Supreme Commander of the Allied Powers). We do not have detailed data about summer time then. According to the law of those days, the last day of summer time was made into 25 hours. What came after 12:59 p.m. of the last day was 00:00 a.m. of the next day. If you have any further questions, please let us know. Sincerely, Japan Standard Time Group Space-Time standards Laboratory Applied Electromagnetic Research Institute National Institute of Information and Communications Technology From: Phake Nick <c933103@gmail.com> Sent: Sunday, September 09, 2018 12:53 AM To: horonet@ml.nict.go.jp Cc: tz@iana.org Subject: [horonet 13333] Inquiry to NICT about Japanese Summer time in 1948-1952. To receivers of this email: Recently, I have read an article, which mentioned the history of Japanese Summer Time Implementation in the past at www.bengo4.com/internet/n_8461/ <http://www.bengo4.com/internet/n_8461/> . In the article, it was mentioned that the summer time (DST) end at 25 hours at the last day of the implementation period. Does that mean the clock would go up to the 25th hours back then and reach 24:59 before it continues toward 00:00 on the next day in standard time? If not then how did the clock switched from Summer Time back to Standard Time back then? Please use the "reply to all" function when replying to the message so that other receivers of the message can also hear answer on the matter. Sincerely, P.N.