A big current that changes every ten years
A Dae-un is a ten-year cycle. Every ten years a new pair of characters, a stem-branch pair, comes in and becomes the backdrop of that decade. The eight characters you were born with, your natal chart, stay the same for life, but a different kind of energy is layered over them every ten years. That is why the same person can read differently depending on which decade they are in.
How the starting age is found
The age at which your first Dae-un begins comes from counting the days from your birth date to a solar term and dividing by three. In the traditional method, three days stand for one year. Which solar term is used depends on whether the cycle runs forward or backward, and that direction is set by the yin or yang of your birth year together with your gender. This is why a calculator asks for your gender when it shows the Dae-un starting age.
How it differs from the yearly and monthly cycles
If a Dae-un is the ten-year current, then the Se-un is the energy that comes in with each year, and the Wol-un the energy of each month. A year is shaped by its Se-un, a decade by its Dae-un, and each month adds its own touch on top. SajuPath's report links these three layers together in plain words, from the big current down to the months.
Where to see yours
Enter your birth date, time and gender in the free calculator and it will show the age at which your Dae-un begins. A Dae-un is not a timetable that fixes what will happen. It is a way of seeing which way the energy around you leans for each decade. Treat it as something to look at for fun and for understanding yourself.
How a decade is read
The characters of a Dae-un are read in the same way as the eight in your chart. A reader looks at what kind of energy the top and bottom characters of that decade carry, how it relates to your Day Master, and whether it fills in an element that was thin in your natal chart or adds to one that was already plentiful. If an element your chart lacks arrives in a Dae-un, that decade is read as one in which that kind of energy gets more room. If an element you already have plenty of arrives again, it is read as a time to think about how you want to use it.
Either way, the point is the direction that energy leans, not a verdict of good or bad. Read it as a lens on each ten years, and keep in mind that what you do inside any decade is up to you.
Questions people often ask
Many people wonder whether life changes overnight when a new Dae-un begins. It is better read as a gradual change in the backdrop over a few years than as a switch that flips everything at once. The age at which the first cycle starts also differs from chart to chart: some begin in early childhood and others in the teens or twenties. What matters is not guessing when things happen, but noticing which way the energy around you leans now and using that as one input to your own choices.