third watch of the night (approx. 11pm to 1am)
Historical timekeeping term from the old Chinese-influenced system dividing the night into five watches. Rare in modern Japanese outside historical or literary contexts.
In the old time system, the third watch corresponds to around 11 p.m. to 1 a.m.
From Chinese 三更 (sāngēng), literally 'third watch'. The term entered Japanese as part of the traditional timekeeping system that divided the night into five equal watches.