K-SaJu 10-year chapters: how the seasons of your life are counted

Ask a Korean friend about their saju and sooner or later they'll mention which ten-year stretch they're in. "My new chapter started last spring" is a pretty normal thing to hear. In K-SaJu (Korean astrology), your eight birth characters never change, but the background behind them does, one decade at a time. This post walks through how those 10-year chapters are built, step by step, with a real example you can check.

Your chart stays put, the scenery changes

Think of your birth chart as a house. It's built the moment you're born and the floor plan never moves, no matter how many times you repaint the walls or swap the furniture around. The 10-year chapters are the weather outside the windows. Some decades are sunny and the doors are wide open. Others are rainy, and you spend more time fixing things up inside.

Each chapter is a pair of characters, a nature on top and an animal below, just like the pillars in your chart. Time is read in layers. A chapter covers ten years, each calendar year brings its own pair, then each month, then each day. The big layer sets the mood and the smaller ones bring the specific events. That's why a K-SaJu reader looks at your chart first, then your current chapter, and only then at this year.

Chapters start from your birth month

Nothing here is random. Your chapters start from your month pillar, the pair for the month you were born, and step through the cycle of 60 pairs one place at a time. If that cycle is new to you, our post on the 60 birthday types explains how it loops.

Say your month pillar is 丙寅 (Sun Tiger). If your chapters move forward, they run 丁卯 (Candle Rabbit), then 戊辰 (Mountain Dragon), and on from there. If they move backward, they run 乙丑 (Vine Ox), then 甲子 (Oak Rat). We calculate eight chapters, which covers about 80 years, and keep counting in the same direction past that when needed.

Forward or backward? Year and gender decide

The ten natures take turns between two kinds. Oak, Sun, Mountain, Steel and Ocean are the outward, active kind. Vine, Candle, Garden, Jewel and Rain are the inward, quiet kind. The rule looks at the top character of your birth year:

• Outward year, born male: chapters move forward
• Inward year, born female: chapters move forward
• Inward year, born male: chapters move backward
• Outward year, born female: chapters move backward

One catch, though. The K-SaJu year flips at the start of spring, around February 4. If you were born in January, the top character of your birth year belongs to the year before. Our guide to why the Korean zodiac year starts in February covers this in detail.

Why we ask for gender

This is the reason the gender question on our form has no default, and you have to tap an answer yourself. Pick the wrong one and every chapter flips direction. We learned this the hard way: a saved profile had the wrong gender, and someone's first chapter came out at age 7 instead of 3.

Here's how big the difference gets. Take two people born at 10:00 am on March 20, 1990, in Korea. Their birth charts are identical, down to the last character. The year is 庚午 (Steel Horse), an outward year, and the month pillar is 己卯 (Garden Rabbit).

• Born male: chapters move forward. The first one is 庚辰 (Steel Dragon), starting around July 1995.
• Born female: chapters move backward. The first one is 戊寅 (Mountain Tiger), starting around December 1994.

Same chart. Same birthday. Two different lists of decades, starting from the very first chapter.

When your first chapter begins

The age your first chapter starts at comes from the solar markers, the twelve points in the year where a new K-SaJu month begins.

1. If your chapters move forward, count the time from your birth to the next marker. If they move backward, count back to the marker before your birth.
2. Divide by three. Three days count as one year, so one day is four months and a two-hour block is ten days.
3. Round to the nearest year. Six months or more rounds up, and the first chapter never starts before age 1.

In the 1990 example, the man's gap to the next marker, divided by three, comes to 5 years and 4 months, so his first chapter starts at about age 5. The woman's gap back to the last marker comes to 4 years and 8 months, which rounds up to 5 as well. Their first chapters begin about seven months apart and carry different characters, even though both say "age 5".

We count that gap down to the minute. Counting by whole days and two-hour blocks, which is how we first did it, pushed some people up a full year whenever their number sat close to the halfway mark, so we switched. On your result you'll see the rounded age plus the month and year it starts, like "from around July 1995".

Ages here count from your birthday, the way they do in the US. Some Korean sources use Korean-style age, which can run a year or two higher, so the same chart can show different starting ages in different places. To decide which chapter you're in today, we compare today's date with the exact date each chapter changes. We never guess from "this year minus birth year".

How a chapter gets judged

A chapter isn't good or bad on its own. It depends on you. What matters is whether it brings the element your chart needs most. If your chart is short on Water, a decade carrying Ocean or Rain tends to read well. If it piles on more of what you already have too much of, it reads heavier. Not sure what your needed element is? Our post on the five elements is a good place to start.

The two halves don't count equally. The top character shows what happens on the surface, and the animal below shows what you actually live through day to day. So in our life reading the animal weighs a bit more, about 60 percent against 40. We also check whether the chapter's animal pairs up with or clashes against your own birthday animal.

Each chapter then lands on one of four levels. We describe them with names like these, and in a large random sample the split came out roughly as follows:

• Full bloom: about 20 percent of chapters
• A tailwind: about 30 percent
• Building as you go: about 30 percent
• Catching your breath: about 20 percent

The old textbooks we learned from agree that most lives hold a mix of tailwind seasons and headwind seasons. Eight sunny decades in a row would be unusual, and so would eight rainy ones.

The slow chapters are building time

If one of your chapters lands on the quieter side, please don't read it as a wasted decade. In K-SaJu it's the stretch where you slow down, sharpen a skill, and sort out the people around you. A tree in winter hasn't given up. It's growing roots you can't see yet.

There's a practical side, too. Once you've figured out that a decade runs against your grain, it gets easier to stop blaming yourself when things move slowly. And when a brighter chapter comes along, you'll have the skills ready to use it.

Our free life reading lists every one of your chapters with its pair of characters, when it starts, and a short reading. It also points out the brightest chapter still ahead of you, picked from the current one and the ones after it, never from the past.