Discovering a Japanese Lantern Clock

By Daniela Corda

As a Post Graduate Diploma student on the Conservation of Clocks program at West Dean College, one of my recent projects has been to restore to safe working order a Japanese lantern clock belonging to the Russell-Cotes Art Gallery & Museum in Bournemouth. The Museum's records classified the clock as Chinese, however, after conducting initial research it became clear that the object conformed to many stylistic features of lantern clocks from the early - mid period of Japanese clock making. These indicators included:

  • Two-winged bell nut
  • Deep bell
  • Verge and foliot escapement
  • Rotating "warikoma" dial
  • Latched case
  • Posted iron frame and iron mobiles

Some of these features are indicative of the temporal time system employed in Japan during the country's Edo period of isolation (1603-1868). It was not until 1873, during the Meiji Reform, that Mean-time and the European calendar were adopted.

The Japanese temporal system divides the day into 12 hours, rather than 24, and six of these "hours" are proportional to daylight and six to darkness. Hence, the adjustable numerals are designed to accommodate variable time intervals within the relative lengths of day and night by season.

The numeral characters are engraved with the traditional 9-4/9-4 numbering, using the zodiacal names of the hours, which count down in reverse order.

During the process of recording and documenting, a conservation approach was employed focusing on stabilising the clock in its current condition.

Treatment included; fabricating missing parts and the mechanical removal of corrosion with a custom made mother-of-pearl scraping tool, a material that retains its shape but is softer than the substrate, so becomes sacrificial, reducing the risk of damaging the ironwork.

During Japan's isolation, the temporal time system suited the predominantly agricultural society: concurrent competition in Europe for the longitude prize was not of their concern. Therefore, it is important to refrain from imposing western motives, descending from a precision-driven approach to clock making, onto an object that has come from a very different context.

Considerations for future work include analysis of the brass alloys and the coating used on the ironwork, as well as investigating the lacquer present on the calendar wheel (pictured above) aiming to provide a more detailed narrative of the social and craft context surrounding the clock.

Due to its age the Museum will impose a stable environment and restricted running hours on the clock to mitigate further losses.