KLIFEMAP.AI

Heavenly stems and earthly branches
— when does the rat hour really start, and why is Seoul 32 minutes late?

The ten heavenly stems and twelve earthly branches in one table, with element, polarity and hidden stems. And the question people ask most — when the rat hour actually begins — answered by querying our engine minute by minute.

The ten heavenly stems — element, polarity, combination and clash

The combinations and clashes come straight from our engine's stem relation table. A combination is not "good" and a clash is not "bad" — they name what kind of relation two characters are in, and how that plays out has to be read alongside the other six characters.

The twelve earthly branches — animal, element, season and hour

Why there are two polarity columns

The polarity of the branches is written differently from book to book, which is where most of the confusion comes from. There are two different scales.

• Position (ti, 體) — zi is first, chou second, and odd positions are yang. Pairing the sexagenary cycle works on this scale
• Inner qi (yong, 用) — the polarity of the strongest hidden stem, the principal qi. This is the scale used when a chart is actually read

The two columns disagree on four branches: zi, si, wu and hai — the detail is set out on the sexagenary cycle page.

When does the rat hour start? Seoul runs 32 minutes late

"The rat hour begins at 11pm" is what you usually read. That is correct — as long as the clock you mean is standard time.

The boundaries above were found by asking our engine minute by minute. We did not write "every two hours" and call it correct. If you were not born in Seoul the boundaries move again — enter your birthplace on the chart page and it calculates from that longitude.

⚠ If you were born close to a boundary, your hour pillar can change. A birth at 11:30pm is in the rat hour by standard time but still in the pig hour by Seoul. One character of the chart changes entirely.

Hidden stems — the stems concealed inside each branch

A branch does not carry a single kind of qi. Two or three stems are concealed inside it, and these are the hidden stems (支藏干). The strongest is the principal qi (正氣), and it is the principal qi that actually sets the branch's element and polarity.

The day counts are how long each hidden stem holds force within the month. The residual qi carries over from the previous month, the middle qi follows, and the principal qi is the branch's own.

How the characters relate

Branch six combinations (六合) — six pairs

Branch clashes (沖) — six pairs

A clash is the facing position — lay the twelve branches in a circle and each clashes with the one directly opposite.

Branch three harmonies (三合) — three characters each

Branch directional combinations (方合) — by season

Common questions

What if I do not know my birth time?

The hour pillar is left empty and the chart is read from the other six characters. We do not invent what we do not know. That said, a missing hour pillar closes off part of the reading, so it is worth checking whether a birth certificate or maternity record has the time on it.

What if I was born during daylight saving time?

Korea observed daylight saving in 1948–1951 and again in 1987–1988. Clocks ran an hour ahead in those periods, so the hour pillar can be off by one. Our engine holds those ranges separately and corrects for them.

Do I have to memorise the stems and branches?

No. Enter a birth date and the engine draws them — the traditional calendar. This table is for looking up what the drawn characters mean.