A number of Ukiyo-e series depict men and women going about their daily business throughout the twelve hours of the day. During the Edo period (1603 - 1868), the Japanese clock was divided into twelve units of time, or ‘hours’, with each one named after one of the zodiacal symbols of the lunar calendar, and with the day being divided up into six daytime hours and six night-time hours. Generally speaking, there has been a tendency for writers on the subject of Japanese art to divide the day into twelve equal segments, in the same way that our day is currently divided into twenty-four segments that are each 60 minutes long. However, as the first six 'hours' of the traditional Japanese clock were counted from dawn and the second six from sunset, the daylight hours were of a different duration to the night-time hours. In addition to this, as the time elapsing between dawn and sunset would alter depending upon the time of the year, with the summer days consisting of more daylight time and the winter days having much less, the hours would change in length from one month to the next.
Take a look at the clock face above that replicates a Meiji era timepiece. It shows not only the traditional twelve hour Japanese system of timekeeping, but also the modern twenty-four hour one that was introduced into Japan in 1872. The inner rings show the modern twenty-four hour clock that we are used to, but with the numbers written in Japanese of course. The left hand side shows the AM hours and the right-hand side shows the PM hours. The thicker of the two small hands counts the minutes, and there are the standard sixty of those. The thinner of the small hands counts the seconds, and again there are the usual sixty. The larger of the three hands tells us which hour it is. As it is in between the numbers five and six, the time must be six o'clock. And as it is pointing to the left-hand side of the clock's face, it is six o'clock in the morning. Following so far? I hope so, as this is where it gets complicated. The outer two rings of the clock face show the traditional Japanese system. The inner ring of the two tells us the number of chimes we might have expected to hear from a shrine bell to mark the time. The outer of the two rings displays the sign of the zodiac which represented that particular hour. The hours were:
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Ne no koku - hour of the rat
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Ushi no koku - hour of the ox
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Tora no koku - hour of the tiger
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U no koku - hour of the hare
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Tatsu no koku - hour of the dragon
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Mi no koku - hour of the snake
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Uma no koku - hour of the horse
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Hitsuji no koku - hour of the sheep
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Saru no koku - hour of the monkey
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Tori no koku - hour of the cock
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Inu no koku - hour of the dog
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I no koku - hour of the boar
Notice that the segments at the bottom of the clock's face, representing the night-time hours, are smaller than the ones at the top of the face to accommodate the varying length of the 'hours'?
The larger hand, pointing to six o'clock in the morning, is also pointing at the character 'tatsu' (for 'tatsu no koku', or the 'hour of the dragon'), so 'tatsu no koku' was six o'clock in the morning. Or was it? As I said before, the amount of daylight would vary throughout the year. As the first six hours of the traditional Japanese clock were counted from dawn and the second six from sunset, and the time we would expect dawn and sunset to arrive would alter on a monthly basis, the clock's rings had to be replaced on the seventh of each month to reflect those changes. Each clock would have come complete with its own set of twelve replacement rings. The larger hand, pointing to six o'clock in the morning, is also pointing at the character 'tatsu' (for 'tatsu no koku', or the 'hour of the dragon'), so 'tatsu no koku' was six o'clock in the morning. Or was it? As I said before, the amount of daylight would vary throughout the year. As the first six hours of the traditional Japanese clock were counted from dawn and the second six from sunset, and the time we would expect dawn and sunset to arrive would alter on a monthly basis, the clock's rings had to be replaced on the seventh of each month to reflect those changes. Each clock would have come complete with a set of twelve replacement rings. So, when we see an Ukiyo-e print, such as this one above from Utamaro's famous series 'Seirō jūni toki tsuzuki' (Twelve Hours of the Green Houses), we may know that the hour being represented is 'tori no koku' (the 'hour of the cock'), as it's written within the bell at the top of the title cartouche on the right, but unless we know the time of year (and make allowances for the amount of daylight time) we cannot, of course, know the exact time of day.
