Six periods

Six periods (六時). The day is divided into

• morning (6–10 a.m.)
• midday (10 a.m.–2 p.m.)
• afternoon (2–6 p.m.)

the night into

• evening (6–10 p.m.)
• midnight (10 p.m.–2 a.m.)
• post-midnight (2–6 a.m.)

Each of the period has 4 hours.