Shaku dokei or pillar clock, Japan, Edo period (1603-1868) - Lot 137

Shaku dokei or pillar clock, Japan, Edo period (1603-1868) It consists of a wooden case, probably ebony, with a gilded brass mechanism at the top inserted in a small removable glass cage. It operates by means of a weight. An openwork needle-shaped index is attached to the weight, which descends in front of plates engraved with Japanese numerals indicating the hours and half-hours, known as "tokis" and "demi-tokis". The clock was wound every day at sunset, with the index in the up position, and lasted 24 hours, with the index in the down position. The plates were moved every 8 or 15 days to display the variable hours. To the right of the clock is a removable graduated scale for setting the variable hours, while the middle represents noon. The movement is in gilded brass. It is built between two openwork plates, adorned with chased scrolls and turned pillars. Its mechanism is based on a meeting wheel with a circular balance fitted with a balance-spring and two inertia weights to regulate oscillations. A small trotteuse hand is fixed to the axis of the meeting wheel, making one revolution in 20 seconds and serving primarily to visualize the movement's operation. The winding key is located in a small drawer at the bottom of the clock. An alarm was originally inserted at the top of the wooden case. It has unfortunately disappeared. Height: 51 cm Cage partly refurbished, one glass replaced in Plexiglas, figures to be replaced in order. These clocks were a unique Japanese invention that simply indicated time on a linear scale as the weight descended. There are many versions of this type of clock, manufactured throughout the Tokugawa period. The earliest used the foliot, then the pendulum and finally the pendulum. The principle is the same for all types of shaku-dokei. The shaku is a Japanese unit of length, about a foot, and many of these column clocks are of this length, but not all.