Saju Calculator

Saju (사주) is the Korean four pillars of destiny. Its full name, sajupalja (사주팔자), means "four pillars, eight characters": the year, month, day and hour of birth each become a pillar of two characters, a Heavenly Stem on top and an Earthly Branch below. Readers look at how the five elements in those characters balance and interact.

Wood, fire, earth, metal and water. In the generating cycle each feeds the next: wood feeds fire, fire makes earth, earth bears metal, metal carries water, water feeds wood. In the controlling cycle water puts out fire, fire melts metal, metal cuts wood, wood breaks up earth and earth dams water. A chart with none of an element is said to lack it, as BTS’ V said of fire in his own chart.

The year pillar changes at Ipchun (입춘), the start of spring around February 4, not on January 1. The month pillar changes on the solar terms (절기) about every 30 days. The day pillar follows the 60-day cycle, and the hour pillar follows two-hour blocks of the clock. The solar term times are verified against the Korea Astronomy and Space Science Institute.

You were born on a day when a solar term began, so the pillar changes partway through that day. Add your birth time to get it. Without a time the hour pillar stays empty too, and the five-element count uses the six characters that are known.

We calculate each idol’s chart from their public birth date and compare it with yours. A saju twin shares your whole day pillar. Next come idols with the same Day Master or the same element, idols whose charts are strong in an element yours lacks, and idols whose Day Master element feeds yours in the generating cycle. Idol birth hours are not public, so their hour pillar is never used.

Your solar (Gregorian) birthday, the one in your passport. Saju is built on the solar terms, so the calculator takes the solar date and the local clock time of your birth.