Saju vs Western astrology: how the two charts compare

The short answer

Western astrology maps the positions of the Sun, Moon, and planets against the twelve zodiac signs and twelve houses at the moment and place of birth. Saju maps the same moment onto a calendar of cycles: four pillars of heavenly stems and earthly branches, read through yin and yang and the five elements. Both start from your birth data; they use completely different symbols to describe it.

What each chart is made of

A Western chart has ten bodies (the Sun, the Moon, and eight planets), twelve signs, twelve houses, and the angles, or aspects, between the bodies.

A Saju chart has four pillars with eight characters. Each character carries an element and a yin or yang polarity, and every character is read by its relationship to the Day Master, the stem of the day of birth.

Your sign vs your Day Master

In Western astrology the headline is your Sun sign, set by where the Sun was. It changes about once a month, so roughly one person in twelve shares yours. In Saju the headline is your Day Master, which changes every day on a ten-day rotation, so roughly one person in ten shares yours, and two people born a day apart usually have different ones.

The Korean zodiac animal is a third thing again: the branch of the year pillar, which changes once a year on a twelve-year cycle. It is often confused with a Western sign, but in Saju it is only one of eight characters.

Planets vs cycles, and the one place they meet

Western astrology is built on an ephemeris: actual planetary positions. Saju uses no planets. Its day and hour pillars simply count forward on continuous cycles of sixty days and twelve two-hour blocks.

The two systems do meet at the Sun. Saju's months begin at solar terms, which are defined by the Sun's position along the ecliptic, the same path the Western zodiac divides into signs. Each Saju month begins when the Sun reaches the 15th degree of a Western sign: the 寅 (Tiger) month, which opens the Saju year at Ipchun, starts at 15° Aquarius around February 4. So a Saju month always spans the second half of one sign and the first half of the next.

Birth time and place

Both systems want an exact birth time. In Western astrology it sets the rising sign and the houses, which shift every few minutes. In Saju it sets the hour pillar, which changes every two hours, and the birthplace is used to correct the clock to true solar time. Without a time, a Western chart loses its houses and rising sign; a Saju chart loses its hour pillar but keeps the Day Master.

Timing and compatibility

For timing, Western astrology follows transits and progressions of the planets. Saju follows ten-year luck pillars and the pillar of each year and month.

For compatibility, Western synastry compares the aspects between two people's planets. Saju compatibility (궁합, gunghap) compares how the two Day Masters relate through the elements, whether stems and branches combine or clash, and whether one chart supplies the elements the other lacks.

Side-by-side comparison

Can you use both?

Yes. They are different lenses, not competing answers, and plenty of people enjoy comparing what each says. Neither has scientific support as a predictor; both are best used for reflection and conversation.