noun
incense clock
A historical timekeeping device that marks time by the burning of a trail of incense. Rarely encountered outside historical or cultural contexts.
江戸時代には、常香盤が時刻を知るために使われていた。
In the Edo period, incense clocks were used to tell the time.
Compound of 常香 (jōkō, 'constantly burning incense') and 盤 (ban, 'board' or 'tray'). The exact historical derivation is uncertain, but the term describes the device's function.