Daeun

This is the part of Saju that has no equivalent in Western astrology, and it is the reason people who dismiss horoscopes still take Saju seriously.

Your eight characters never change. What changes is the pair of characters layered over them for each decade of your life. A chart that is starved of Water for thirty years and then enters two Water decades does not behave like the same chart.

Which decade you are standing in explains far more about why a period of life felt the way it did than anything in the birth chart alone.