Annual Advancement
小限
One palace per year — beginning at the Life Palace in the birth year and moving counter-zodiacally thereafter.
Annual Advancement (小限) assigns one palace to each year of life. In the year of birth it sits on the Life Palace; each subsequent year it steps one palace counter-zodiacally, completing a circuit every twelve years. The palace for any given year is therefore fixed by age modulo twelve.
The year here is a year of life, not a calendar year: the palace changes on the native's own birthday, not at New Year, not at the lunar new year, and not at Start of Spring. This anchor is specific to Annual Advancement — the Annual Forecast layer above it turns over at a different point.
The palace a year lands on tells you which department of life that year is about; what actually happens there is read from the bodies transiting that palace, its opposite palace, and its two trine palaces.