庚午 Day Pillar (Geng Wu): Na Yin and elements
What the Day Pillar shows
The 庚午 (Geng Wu) Day Pillar pairs the Yang Metal Heavenly Stem with the Horse Earthly Branch. In a full chart this is the pillar readers use to locate the Day Master — the reference point from which other stems and branches are compared.
The Na Yin image
In the Na Yin tradition, the 庚午 pair carries the image "Earth by the Roadside" (路旁土, Lu Pang Tu). Na Yin is a poetic layer that assigns a combined image to each consecutive pair of pillars. It is a traditional vocabulary for noticing quality and texture, not a prediction.
How the stem and branch interact
The stem is Yang Metal (Metal) and the branch is associated with Fire; in this pairing, the branch element controls the stem element. Traditional readers describe this configuration as carrying productive tension.
A careful reading boundary
A Day Pillar is a calculated position inside a Four Pillars chart, not a verdict about a person. Read it with the Month Pillar, the visible elements, and the certainty of the birth record.