Until the late 19^th century, in Japan time was not broken down into days with 24 equally long hours; instead, day and night would be divided into six time units each, called “toki”. As the days of summer are longer than the nights, in summer the daytime “toki” were longer than the night time “toki”. In winter it was the other way around.

Japanese Clocks with Round Dials

In the 16^th century, Portuguese Jesuits brought the first mechanical clocks from Europe to the Far East while on their missionary travels.

To show the Japanese time system, lantern clocks, so-called “wadokei”, were developed.

There were two different models: One consisted in making a uniformly running clock such that the position of the “toki” markings could be changed. In the second model, the clock movement ran at different rates, depending on whether it was daytime or night time. For this purpose, two foliot balances with moveable weights were added to regulate the rate. After six “toki”, one foliot balance bar would automatically be replaced by the other. In both versions, the clocks had to be adjusted at intervals of approximately one fortnight.

Japanese Pillar Clocks

These clocks with the elongated dial (see overleaf) cannot be immediately recognized as timepieces. The clock movement is in the upper portion; the moveable “toki” plates are located below it. A pointer moves from top to bottom within 24 hours’ time. Winding the movement causes the pointer to return to the top.

Western Influences

In 1872 the Japanese government adopted the European system of time. This signified the end of the  wadokei clocks.
European pocket watch makers created special dials for the Asian market which usually displayed the European 24-hour divisions and the Chinese signs of the zodiac.