Sangeng 三更 [the third geng]

Geng is the unit of time indicated night time; a night is divided into five shifts, each equivalent to two hours of the modern unit of time. It originated from the fact that the night shifts of the imperial palace in the Han Dynasty were divided into five shifts from 7:00 p.m. to 5:00 a.m., with each two hours being one geng. So sangeng 三更 [the third geng] corresponded to 11:00 pm to 1:00 am the other day, which is also zishi 子時 [the hour of rat] in Chinese zodiac time. For more information, see the entry of Chinese zodiac time.