日本如何学会遵守同一时间？

Sources consulted 16 September 2026. The essay distinguishes seasonal hours, calendar dates, geographical standard time, and synchronization. Historical lunisolar month numbers are not silently treated as Gregorian dates.

1. [1]

   The Seiko Museum Ginza, collection entry 「二挺天符目覚付袴腰櫓時計」, late Edo period. See the catalogue's account of the two regulators, automatic dawn/dusk switching, and seasonal adjustment. https://museum.seiko.co.jp/collections/traditional_Japanese_clock/collect001/

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2. [2]

   The Seiko Museum Ginza, 「不定時法の説明」, explanation of seasonal time and the alternatives of adjusting the regulator or hour-marker spacing. No new measurements are derived from its diagrams. Dawn and dusk are retained rather than equating historical conventions with a single modern astronomical definition of sunrise and sunset. https://museum.seiko.co.jp/knowledge/relation_16/

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3. [3]

   Saitama City, 「江戸時代から続く鐘の音をお楽しみください（市指定文化財『時の鐘』）」, historical paragraphs, updated 10 August 2022. Supports the 1671 institution, 1720 recasting, and former twelve daily soundings. Present schedules are not used as evidence of an unchanged Edo routine. https://www.city.saitama.lg.jp/004/001/003/001/p013686.html

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4. [4]

   The Seiko Museum Ginza, 「江戸時代の暮らしと時間」, passages on time bells and their support. Used for the organization and financing of an audible service, not its broader generalizations about uniquely Japanese punctuality or perfect synchronization. The discussion of a bell's physical reach is explanatory reasoning, not a historical acoustic survey. https://museum.seiko.co.jp/knowledge/relation_07/

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5. [5]

   National Diet Library, 本の万華鏡 32, “鉄道が変えたコト・モノ,” chapter 1, 「時刻の統一～暮れ六つから何時何分へ～」. See the narrative and object captions on minute-based railway schedules and the changing written forms for ji. The different admission deadlines in separate documents are not conflated: the notice examined in note 6 specifies three minutes. https://www.ndl.go.jp/kaleido/entry/32/2.html

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6. [6]

   National Archives of Japan, 「汽車運転時限并賃金表上達」, 1872, Kōbunroku, call number 公00681100, item 021. See the archive's explanation and modernized transcription; See its single-page reproduction as an actual PDF image. The ten-minute arrival instruction, three-minute closure, and qualification about exact punctuality appear in that document. It was prepared for the proposed opening arrangements; its stated lunar date is not asserted as the eventual Gregorian opening day. https://www.archives.go.jp/learning/archive_collection_3/collection_6/ ; https://www.archives.go.jp/learning/archive_collection_3/collection_6/pdf/file.pdf

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7. [7]

   National Diet Library, 日本の暦, chapter 1, 「暦の歴史」, subsection on the Meiji calendar reform. See the account of the change from the third day of the twelfth lunar month to 1 January 1873 and the contents of the first solar-calendar edition. Consequences for coordinating dates and hours are distinguished from a measured survey of household reactions. https://www.ndl.go.jp/koyomi/chapter1/s2.html

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8. [8]

   Same National Diet Library history, sections on the Jōkyō and subsequent Edo-period calendars. Used only to establish a pre-Meiji history of calendrical revision; not a detailed reconstruction of Shibukawa's observations or a claim that calendar computation and clock synchronization were identical tasks. https://www.ndl.go.jp/koyomi/chapter1/s2.html

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9. [9]

   National Institute of Information and Communications Technology, 「日本標準時」, explanation of longitude and the 135-degree reference. The rotation arithmetic is explanatory; the historical nineteenth-century standard is not described as already using modern atomic time or Coordinated Universal Time. https://www.nict.go.jp/sts/jst.html

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10. [10]

    Japan Clock & Watch Association, “Japan Standard Time,” for the 1886 ordinance, implementation on 1 January 1888, and 135 degrees east. See also NICT's explanation in note 9. The essay does not adopt the association's compressed account as proof that the 1884 international conference itself imposed every later national time zone. https://www.jcwa.or.jp/en/etc/knowledge/jst.html

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11. [11]

    National Diet Library, chapter 1 of “鉄道が変えたコト・モノ,” paragraphs and caption concerning the 1887 「営業線路従事諸員服務規程」. This is the library's explanation of the rule and its clock-comparison requirements, not a reading of every provision or a certification that all stations complied. https://www.ndl.go.jp/kaleido/entry/32/2.html

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12. [12]

    NICT, 「日本標準時の歴史」, entries for 1940 and April/August 1948. The frequency service beginning in 1940 is distinguished from the minute/second signal experiment and regular second reporting in 1948. This is not a claim that these were Japan's first time signals by any medium. https://www.nict.go.jp/sts/history.html

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