| Japan Standard Time | |
|---|---|
| Time zone | |
| UTC offset | |
| JST | UTC+09:00 |
| Current time | |
| 04:01, 26 November 2025JST[refresh] | |
| Observance ofDST | |
| DST is not observed in this time zone. | |
| Japan Standard Time | |||||
|---|---|---|---|---|---|
| Japanese name | |||||
| Kanji | 日本標準時 | ||||
| Kana | にほん ひょうじゅんじ にっぽん ひょうじゅんじ | ||||
| |||||
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Japan Standard Time (日本標準時,Nihon Hyōjunji;JST), orJapan Central Standard Time (中央標準時,Chūō Hyōjunji;JCST), is the standardtime zone inJapan, 9 hours ahead of UTC (UTC+09:00).[1] Japan does not observe daylight saving time, though its introduction has been debated on several occasions. DuringWorld War II, the time zone was often referred to asTokyo Standard Time.
Japan Standard Time is equivalent toKorean Standard Time,Pyongyang Time (North Korea),Eastern Indonesia Standard Time,East-Timorese Standard Time,Palau Time, andYakutsk Time (Russia).
Before theMeiji era (1868–1912), each local region had its own time zone in which noon was when the sun was exactly at itsculmination. As modern transportation methods, such as trains, were adopted, this practice became a source of confusion. For example, there is a difference of about 5 degrees longitude betweenTokyo andOsaka and because of this, a train that departed from Tokyo would arrive at Osaka 20 minutes behind the time in Tokyo. In 1886, Ordinance 51 was issued in response to this problem, which stated:
Ordinance 51 (on the precise calculation of time using the Prime Meridian) – July 13, 1886
- Theprime meridian passes through England'sGreenwich Observatory.
- Longitudes are calculated using the prime meridian, counting 180 degrees either east or west. Positive degrees are east, negative degrees are west.
- On January 1, 1888,135 degrees east longitude will be set as the standard meridian for all of Japan, allowing precise times to be fixed.[2]
According to this, thestandard time (標準時,hyōjunji) was set 9 hours ahead ofGMT (UTC had not been established yet). In the ordinance, the first clause mentions GMT, the second defines east longitude and west longitude and the third says the standard time zone would be in effect from 1888. The city ofAkashi inHyōgo Prefecture is located exactly on 135 degrees east longitude and subsequently became known asToki no machi (Town of Time).
With theannexation of Taiwan in 1895, Ordinance 167 (pictured on the right) was issued to rename the previous Standard Time toCentral Standard Time (中央標準時,Chūō Hyōjunji) and establish a newWestern Standard Time (西部標準時,Seibu Hyōjunji) at120° longitude as the time zone for the JapaneseMiyako andYaeyama Islands, as well as Taiwan and itsPenghu Islands.[3] WhileKorea cameunder Japanese rule in 1910,Korea Standard Time of GMT+08:30 continued to be used until 1912, when it was changed to Central Standard Time.
Western Standard Time, which was used inTaiwan and some parts ofOkinawa, was abolished by Ordinance 529 in 1937 and replaced by Central Standard Time in those areas.[4] Territories occupied by Japan during World War II, includingSingapore andMalaya, adopted Japan Standard Time for the duration of their occupation, but reverted afterJapan's surrender.
Between 1948 and 1951occupied Japan observeddaylight saving time (DST) from the first Saturday in May at 24:00 to the second Saturday in September at 24:00 (with the exception of 1949, when the spring forward transition was the first Saturday in April at 24:00).[5] More recently there have been efforts to restore daylight saving time in Japan but these have not succeeded.[6][7]
In May 2013, former Tokyo governorNaoki Inose proposed permanently moving the country's time zone ahead by 2 hours to better align global markets and make Japan's stock market to be the first to open in the world at any given time.[8]
The two-time-zone system was implemented in Japan between January 1896 and September 1937:
| Time offset | Name | Japanese | Romanization | Region |
|---|---|---|---|---|
| GMT+08:00 | Western Standard Time | 西部標準時 | Seibu Hyōjunji | Western Okinawa and Taiwan (see alsoTime in Taiwan) |
| GMT+09:00 | Central Standard Time | 中央標準時 | Chūō Hyōjunji | Japan mainland and Korea (see alsoKorea Standard Time) |
From October 1937, Central Standard Time was also used in western Okinawa and Taiwan.
TheIANA time zone database contains one zone for Japan in the filezone.tab, namedAsia/Tokyo.
From 1948 to 1952, Japan observed daylight saving time (DST) between May and September every year. TheUnited States imposed this policy as part of theAllied occupation of Japan. In 1952, three weeks before the occupation ended, the Japanese government, which had been granted increased powers, abolished daylight saving time, and the Allied occupation authorities did not interfere.[9] Since then, DST has never been officially implemented nationwide in Japan.[10]
Starting in the late 1990s, a movement to reinstate DST in Japan gained some popularity, aiming at saving energy and increasing recreational time. TheHokkaido region is particularly in favour of this movement because daylight starts as early as 03:30 (in standard time) there in summer due to its high latitude and its location near the eastern edge of the time zone, with much of the region's solar time actually closer to UTC+10:00. Because of this, the sun sets shortly after 19:00 in much of the eastern part of the country (in Tokyo, the latest sunset of the entire year is 19:01, from June 26 to July 1, despite being at 35°41'N latitude). Since 2000, a few local governments and commerce departments have promoted unmandated hour-earlier work schedule experiments during the summer without officially resetting clocks.[11]
The Council on Economic and Fiscal Policy of theCabinet Office is expected[when?](written October 2013) to propose that the Japanese government begin studying DST in an attempt to help combatglobal warming.Japanese former Prime MinisterShinzō Abe made a significant effort to introduce daylight saving time, but was ultimately unsuccessful.[12] However, it is not clear that DST wouldconserve energy in Japan. A 2007 simulation estimated that introducing DST to Japan would increase energy use inOsaka residences by 0.13%, with a 0.02% saving due to lighting more than outweighed by a 0.15% increase due to cooling costs; the simulation did not examine non-residential buildings.[13]
On May 22, 2013,Governor of TokyoNaoki Inose proposed a two-hour advance (UTC+11) Japan Standard Time at an industry competitiveness conference. Its purpose is to enhance the influence of theJapanese financial market by starting early in theTokyo financial market. The Japanese government has decided to consider this proposal.[14] However, there has been no specific discussion of this proposal for more than ten years.
（明治十九年七月十三日勅令第五十一号）
JapaneseWikisource has original text related to this article:明治十九年勅令第五十一号
