Asia/Tokyo

Time zone identifier: Asia/Tokyo

Current civil offset: +09:00 (JST)

Current DST state: Observing Standard Time

First standard time adoption: Adopted on 1887-12-31

Local Mean Time (LMT): +09:18:59 based on geographic meridian

Total recorded transitions: 9 transitions across 3 distinct offsets

Associated countries: AU, JP

Aliases (Link targets): Japan

Historical Offset Step Chart (1880 to Present)

Text summary: Asia/Tokyo shifted between 3 distinct offsets from 1887-12-31 through the modern era.

UTC Instant	Local Wall Time	Shift	Abbreviation	DST	Effect
`1887-12-31T15:00:00Z`	`1888-01-01 00:00:00`	+09:18:59 → +09:00	`JST`	No	overlap
`1948-05-01T15:00:00Z`	`1948-05-02 01:00:00`	+09:00 → +10:00	`JDT`	Yes	gap
`1948-09-11T15:00:00Z`	`1948-09-12 00:00:00`	+10:00 → +09:00	`JST`	No	overlap
`1949-04-02T15:00:00Z`	`1949-04-03 01:00:00`	+09:00 → +10:00	`JDT`	Yes	gap
`1949-09-10T15:00:00Z`	`1949-09-11 00:00:00`	+10:00 → +09:00	`JST`	No	overlap
`1950-05-06T15:00:00Z`	`1950-05-07 01:00:00`	+09:00 → +10:00	`JDT`	Yes	gap
`1950-09-09T15:00:00Z`	`1950-09-10 00:00:00`	+10:00 → +09:00	`JST`	No	overlap
`1951-05-05T15:00:00Z`	`1951-05-06 01:00:00`	+09:00 → +10:00	`JDT`	Yes	gap
`1951-09-08T15:00:00Z`	`1951-09-09 00:00:00`	+10:00 → +09:00	`JST`	No	overlap

Source: asia (Lines 2167 to 2168)

Zone	NAME		STDOFF	RULES	FORMAT	[UNTIL]

tzdb guarantees accuracy for timestamps from 1970 onwards. Transitions prior to 1970 represent best-effort historical reconstructions.