Edo Divisions of Day

Early Japanese “Hours”

The Japanese day was divided into twelve toki (hours), which had been used from the earliest antiquity (see above) and were adopted by the Japanese. The daylight toki would start when it was light enough to work and was determined when it was light enough to see three lines on the palm of one’s hand. It should be noted that the terms ‘sunrise’ and ‘sunset’ were not used since the Japanese counted twilight in with the day toki. Also, very few Japanese people could observe both the sunrise and sunset as the country was so mountainous.

Each period of day light and night were each split equally into six toki. Thus a daylight toki was longer in summer than in winter and vary as the seasons progressed. It was generally accepted that adjustments were made each two weeks or thirteenths of a half year – Spring to Autumn equinox respectively.

The hours were not numbered, but were called after the names of animals. During the period of transition before the modern method was entirely adopted, numbers were used beside the animal names. They were counted in a very peculiar way. Their relative values as compared with ours are given in the table below as they correspond to a.m. and p.m.

Today, it is unclear when an old text says “at the hour of the ox” (for example) that it means at the beginning of that toki or in the middle of it.

The graphic below shows the variation in the length of days and nights. The top bar represents summer, the bottom winter; the middle is spring and autumn. Japan sitting on the longitude of 35 degrees gives less variance than that of the UK.

The Japanese populace used temporal time; however, the astronomers relied on a separate system of celestial time.

Another Japanese time system was known as rokuji, which meant literally “six hours” (i.e. roku – 6 and ji – hours).  In this system each day was divided into the following six periods:

  1. Shincho – morning
  2. Nitchu – afternoon
  3. Nichibotsu – evening
  4. Shoya – early night
  5. Chuya – midnight or Hanya – “half night”
  6. Koya – after night

According to some sources, this system was derived from the Buddhist religious practice of praying to Amida, at six intervals throughout the day, a practice which was known as rokuji no raisan and literally means “to pay homage at the six hours”.

Bell Strikes

Incense clocks were the early method for measuring time in Japan. These fuel clocks, which reduced matter by fire, were the only means of telling the time. The only way the priests could correctly ring the bells was to see how much matter was left. This was true both of incense clocks and candle clocks.

The Japanese people were so used to this system that they carried it over to mechanical clocks. To this timekeeping system they added a method of ringing bells. At first six bells were used, one for each hour, but later in the Asuka period in the 6th Century AD, complications arose since one, two and three bells were used to summon the faithful to prayer and other religious ceremonies, so four to nine bells were used to peel the six hours.

The unusual assignment of the number of bell strikes for each hour was universally adopted across all Japanese striking clocks as 9-8-7-6-5-4 between midnight and noon, and noon to midnight. No records survive as to the origin of the system. However, there are various theories, including:

  • the use of the traditionally lucky number nine at midnight and noon
  • the avoidance of a 1, 2 or 3 bell strike as these were used by temples
  • an arithmetic computation of 10-1, 10-2, etc.
  • an arithmetic computation of the lucky number nine as 1×9, 2×9, etc. and then dropping first digit
  • linear measurement of the traditional burning down of candles, or the draining of water clocks

No one knows exactly.


The conventional way to mark time during the Edo period was a single strike on a bell followed by an interval of about a minute and then a second strike followed quickly by a third. A long pause and then the correct number of strokes then followed this with about ten seconds between each, except the last two. The last stroke followed quickly in order to indicate the end of the count.


Japanese Hour                    Japanese Name              English Name

9          Ku                      Ne                               Rat

8       Hachi                     Ushi                            Ox

7       Shichi                    Tora                            Tiger

6        Roku                     U                                Hare/Rabbit

5          Go                       Tatsu                          Dragon

4         Yon                      Mi                              Snake

9          Ku                      Uma                            Horse

8       Hachi                     Hitsuji                        Goat/Sheep

7       Shichi                    Saru                            Monkey

6        Roku                     Tori                            Cock

5          Go                       Inu                             Dog

4         Yon                      Li                               Boar


In July 1892, Thomas Egleton wrote an article entitled “Ancient Methods of Recording Time in Japan” in the School of Mines Quarterly, stating

Time in Japan, except in the remote towns, is now recorded as in Europe. Foreign clocks and watches have now taken so firm a hold with the people that they will not be displaced. The Yankee clock is to be seen everywhere and has driven out other timepieces. The names of the largest American manufacturers, printed or engraved on glass, is one of the ornaments of the watchmakers shops in almost every large city in Japan.

The ancient methods are fast disappearing and with the introduction of the new the old is laid aside. The most interesting and valuable time-pieces constructed for keeping time by the ancient method can now be found in the curio shops and purchased for almost nothing, being discarded as no longer of use. They are models ordinarily taken from the Dutch time pieces of the 17th century and are extremely interesting as relics of methods of recording time which have long ago disappeared and of escapements no longer used. For a historical horological museum a collection could be made in Japan for almost nothing, as, except among the curio dealers of the large towns, thronged by European visitors, the finest ancient timepieces are of almost no value.”