Edo Period Time Conversion (Seasonal Hours)
Also listed in：Calculating the Calendar > Time and Time of Day
Convert the time notation used by commoners during the Edo period (the “indefinite time system”) to modern time.
・The traditional seasonal timekeeping system was based on sunrise and sunset. The times when the solar altitude was -7.36 degrees were called Ake-mutsu (dawn) and Kure-mutsu (dusk).
・Daytime and nighttime were each divided into 6 equal parts, called one daytime or nighttime temporal hour (ittoki). Their lengths varied with the season and location.
・This calculator uses the 24 solar terms to represent the season and the area around Ryōgoku in Edo as the location.
・Conversions to modern time may differ according to interpretations of the historical period.
・Daytime and nighttime were each divided into 6 equal parts, called one daytime or nighttime temporal hour (ittoki). Their lengths varied with the season and location.
・This calculator uses the 24 solar terms to represent the season and the area around Ryōgoku in Edo as the location.
・Conversions to modern time may differ according to interpretations of the historical period.
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