LANTERN CLOCK Ca. 1790 Japan
JAPANESE LANTERN CLOCK
The weight-driven movement is constructed between vertical bars and has going, striking and alarm trains. The going train has a vertical verge escapement with two foliots, one for the day and one for the night. The movement can be regulated by moving the weights on the foliot. The striking, which is regulated by a count wheel, indicates the hours fully on a bell and the half hours with one stroke.
The brass dial plate has a red painted centre with a dragon painted in gold. It has a brass chapter ring, which turns fully in 24 hours indicating the time by a fixed hand. The chapter ring is divided into 12 parts, with Japanese signs of the Zodiac. The inner track of the chapter ring is divided into 2 x 6 toki from 4 to 9, also with engraved Japanese characters. Each toki is subdivided into 9 strokes, marked on the inside of the chapter ring.
The engraved brass case has steel bottom and top plates, between which the steel movement is constructed. The brass front and back, as well as the brass doors to the sides are profusely engraved and situated between the steel top and bottom. The clock is surmounted by a large shaped bell, secured with a brass butterfly nut, of which the curled wings are made of steel.
Duration 1 day
Height 51 cm.
Width 18 cm.
Depth 20 cm.
– W. Brandes, Alte Japanische Uhren.
– N.H.N. Mody, Japanese clocks.
Japanese timekeeping was very different from timekeeping in the western world. Instead of the hour having a fixed value, the length of an hour in Japan, called toki in Japanese, varies according to the length of day and night. Both day and night are divided into 6 toki, spread over the period from sunrise to sunset and from sunset to sunrise. In summer the days are longer than the nights and therefore a toki during the day is longer than one during the night. In winter this is the other way around. For this reason Japanese clocks have chapter rings with movable chapters, so that the length of the toki can be modified. There are also clocks with a fixed chapter ring. In this case the clock’s beat rate changes by moving the weights on the foliot to slow down or accelerate the clock. This is seen mainly in older clocks.
The numerals on the clocks run from 9 to 4. In Japan number 9 was holy. Each toki, 12 in total, also had its own zodiacal symbol which is depicted on the chapter ring, around the hour numerals.