Vernal Equinox — Born Hour
Vernal Equinox: day and night equalize at 0° longitude — the balance peak inside Mao month.
Overview
Chun Fen (春分) is Mao month's Zhong Qi at ecliptic longitude 0°. Light and dark share the day.
Pentads: 玄鸟至、雷乃发声、始电. Swallows return in many regions; Chinese calendrical poetry treats this as yin-yang balance.
Customs: egg-standing games, spring outings (踏青), offering to the sun (祭日). Entertainment and rite — not pillar rules.
Use equinox to remember true solar time: near boundary instants, clock time alone can misplace the Hour Pillar.
Phenology (three pentads)
Three pentads: swallows arrive; thunder sounds; lightning appears.
Classical citation
Classical: at equinox yin and yang are half and half — day equals night.
Month command contrast
Month command: Mao mid-point; balanced month climate.
Related entries
How to read it on a chart
Find Vernal Equinox in the almanac or chart engine output for your birth year and compare the instant with true solar time.
Jie nodes can move the Month Pillar; Zhong Qi deepen the same month without switching branch.
Limits
Vernal Equinox is a calendrical node and cultural festival, not a weather guarantee or personal luck verdict.