Korean Saju

This calculator turns a Gregorian birth date into a saju chart, the grid of heavenly stems (천간) and earthly branches (지지) that Korean practice took from the Chinese sexagenary calendar. It always builds three pillars, year, month and day, and adds an hour pillar only when you pick a birth hour. Each pillar pairs one of ten stems with one of twelve branches. Every stem and branch carries one of the five elements, and each stem is also yin or yang. The stem of the day pillar is treated as your day master.

A few simplifications matter. The year always turns on 4 February, a fixed stand-in for Ipchun, the start-of-spring solar term, which can fall on the 3rd, 4th or 5th. Month boundaries use fixed approximate dates for the twelve solar terms rather than their astronomical times, so a birth within a day of one deserves a second look. The day changes at midnight, and the hour is used as entered, with no adjustment for longitude or summer time. The element tally counts only the visible stems and branches, leaving out the hidden stems many practitioners weigh. Gender affects one thing: whether the ten-year Daeun cycles run forwards or backwards.

Take 14 March 1990, female, hour unknown. The date falls after 4 February, so the year counts as 1990 and the year pillar is 庚午 Gyeong-o, yang Metal over the Horse. The day count lands on 戊寅 Mu-in, yang Earth over the Tiger, which makes the day master Mu, the Earth stem the page pictures as a mountain. Without an hour there are three pillars and six elements to tally. A yang year stem with a female chart sends the luck cycles backwards, and the eight days back to the solar term on 6 March, divided by three, place the first cycle at about age three.

Read the day pillar first, because everything else is measured against its stem. The element chart shows which elements cluster and which are absent. An empty element is not a flaw; it can prompt you to notice where you look for that quality in other people or settings. The twelve life stages compare your day stem with each branch and work best as a vocabulary for momentum, not as verdicts. Daeun periods suggest a shifting emphasis across decades, and the highlighted one uses your exact age today, though the cycle start ages themselves are rounded to whole years. The compatibility score looks only at the two day pillars and year branches, held between minus five and five.

The chart gives you a structured set of symbols for reflection, though it cannot describe your circumstances, choices or the people around you.