incense clock
A historical timekeeping device that marks time by the burning of a trail of incense. Rarely encountered outside historical or cultural contexts.
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.