traditional Japanese clock; Edo-period clock
Refers to mechanical clocks made in Japan, mainly during the Edo period, that told time according to the traditional Japanese temporal hour system (不定時法).
博物館で江戸時代の和時計を見た。
I saw an Edo-period Japanese clock at the museum.
和時計は季節によって一刻の長さが変わる仕組みになっている。
Traditional Japanese clocks are designed so that the length of one 'koku' changes with the seasons.
不定時法 is the temporal hour system used by 和時計, where daytime and nighttime were each divided into six equal periods whose length varied by season.
Formed from 和 “Japanese-style” and 時計 “clock.” The compound has regular sequential voicing, producing どけい.